diff --git a/cron/jobs.py b/cron/jobs.py
index f2476f78c6..9142d99054 100644
--- a/cron/jobs.py
+++ b/cron/jobs.py
@@ -2727,6 +2727,17 @@ def claim_job_for_fire(
         # stamping it would make completed_occurrence() skip that slot when it arrives.
         manual_fire = force or manual or job.get("manual_run_at") == job.get("next_run_at")
         instant = None if manual_fire else scheduled_instant(job.get("next_run_at"))
+        # A scheduled tick only ever fires when now >= next_run_at
+        # (_evaluate_due_job returns False while the stored occurrence is still
+        # in the future), so a claim arriving BEFORE the stored next occurrence
+        # cannot be the tick that owns it — it is a manual / dashboard / webhook
+        # fire and must stay occurrence-free. Binding it would make run_one_job
+        # stamp that FUTURE instant completed in the ledger: later manual fires
+        # are then refused ("Job is already being fired by the scheduler") and
+        # the scheduled tick dedupe-skips its real delivery (2026-09-08 live:
+        # a manual run at 19:53 consumed the next day's 19:00 occurrence).
+        if instant is not None and datetime.fromisoformat(instant) > now:
+            instant = None
         if instant and completed_occurrence(job, instant):
             if job.get("schedule", {}).get("kind") in {"cron", "interval"}:
                 nxt = compute_next_run(job["schedule"], now.isoformat())
diff --git a/cron/scheduler_provider.py b/cron/scheduler_provider.py
index 9ec19c0fde..343d2918a6 100644
--- a/cron/scheduler_provider.py
+++ b/cron/scheduler_provider.py
@@ -165,7 +165,9 @@ class CronScheduler(ABC):
         attempt (even if the job failed); False if the claim was lost or the job is gone.
         ``manual`` marks an off-tick run-now (dashboard trigger): the claim must not stamp
         ``next_run_at`` as the occurrence, or that slot is skipped when it arrives. Webhook and
-        misfire fires run the slot that is due and keep the stamp."""
+        misfire fires arriving at/after the due instant run that slot and keep the stamp; a fire
+        arriving BEFORE the stored instant is off-tick like ``manual`` and stays occurrence-free
+        (it cannot be the tick that owns a future slot)."""
         claimed_job = self.claim_fire(job_id, force=force, manual=manual)
         if claimed_job is None:
             return False
diff --git a/tests/cron/test_manual_fire_occurrence.py b/tests/cron/test_manual_fire_occurrence.py
new file mode 100644
index 0000000000..f1016e1c9a
--- /dev/null
+++ b/tests/cron/test_manual_fire_occurrence.py
@@ -0,0 +1,188 @@
+"""Manual (non-tick) fires must not consume the next scheduled occurrence.
+
+Regression context (2026-09-08, live install): after the scheduled 19:00 run of
+job d88fde170fb4, a manual run at 19:53 claimed the occurrence instant at
+next_run_at (= tomorrow 19:00) and the executions ledger stamped that future
+instant completed. From then on (a) every later manual fire was refused with
+"Job is already being fired by the scheduler; not run again." and (b) the next
+scheduled tick dedupe-skipped its real delivery and merely advanced
+next_run_at.
+
+The ticker never fires early: ``_evaluate_due_job`` returns False while
+next_run_dt > now. So any fire claim arriving BEFORE the stored next
+occurrence cannot be the tick that owns it — it is a manual / dashboard /
+webhook fire and must stay occurrence-free (its ledger row carries
+scheduled_instant=NULL). Ticks that fire on time or late (catch-up) keep the
+exact at-most-once occurrence identity unchanged.
+
+Clock is faked at ``cron.jobs._hermes_now`` (the only binding the claim, mark
+and due-decision paths read); ledger claimed_at stamps use the real clock,
+which no assertion depends on.
+"""
+from datetime import datetime, timedelta
+
+import pytest
+
+
+@pytest.fixture
+def temp_home(tmp_path, monkeypatch):
+    """Isolated HERMES_HOME so jobs.json doesn't touch the real store."""
+    monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+    yield tmp_path
+
+
+def _patch_now(monkeypatch, dt):
+    import cron.jobs as jobs_mod
+
+    monkeypatch.setattr(jobs_mod, "_hermes_now", lambda: dt)
+
+
+def _simulate_last_scheduled_run(job_id, monkeypatch):
+    """One on-time scheduled fire completed: occurrence-bound ledger row for the
+    stored next_run_at, then mark_job_run re-arms to the following occurrence."""
+    from cron import executions, jobs
+    from cron.occurrences import scheduled_instant as canonical_instant
+
+    n0 = datetime.fromisoformat(jobs.get_job(job_id)["next_run_at"])
+    _patch_now(monkeypatch, n0 + timedelta(seconds=5))
+    instant = canonical_instant(jobs.get_job(job_id)["next_run_at"])
+    row = executions.create_execution(job_id, source="builtin", scheduled_instant=instant)
+    executions.finish_execution(row["id"], success=True)
+    jobs.mark_job_run(job_id, success=True)
+    from cron.occurrences import completed_occurrence as _completed
+
+    assert _completed(jobs.get_job(job_id), instant) is True
+    return instant
+
+
+def _midcycle_now(job_id):
+    """Clock between the completed run and the next occurrence: 23h before the
+    stored next_run_at. compute_next_run from this instant still yields the
+    stored occurrence (the live 19:53 shape)."""
+    import cron.jobs as jobs
+
+    return datetime.fromisoformat(jobs.get_job(job_id)["next_run_at"]) - timedelta(hours=23)
+
+
+def _manual_fire_and_complete(job_id):
+    """The production manual-run sequence — claim, run_one_job's ledger row
+    (source='direct', scheduled_instant=job['_scheduled_instant']), terminal
+    finish, mark_job_run — without the agent/session machinery."""
+    from cron import executions
+    from cron.jobs import claim_job_for_fire, mark_job_run
+
+    claimed = claim_job_for_fire(job_id, return_job=True)
+    assert isinstance(claimed, dict)
+    row = executions.create_execution(
+        job_id, source="direct", scheduled_instant=claimed["_scheduled_instant"])
+    executions.finish_execution(row["id"], success=True)
+    mark_job_run(job_id, success=True)
+    return claimed
+
+
+def test_manual_fire_between_scheduled_runs_does_not_consume_next_occurrence(temp_home, monkeypatch):
+    """A mid-cycle manual run must stay occurrence-free: its ledger row carries
+    scheduled_instant=NULL, the next occurrence stays deliverable, and the next
+    scheduled tick actually fires instead of dedupe-skipping."""
+    from cron import executions
+    from cron.jobs import _DueScan, _evaluate_due_job, create_job, get_job
+    from cron.occurrences import completed_occurrence
+
+    job = create_job(prompt="x", schedule="0 19 * * *", name="evening")
+    jid = job["id"]
+    _simulate_last_scheduled_run(jid, monkeypatch)
+    next_occurrence = get_job(jid)["next_run_at"]
+
+    _patch_now(monkeypatch, _midcycle_now(jid))
+
+    claimed = _manual_fire_and_complete(jid)
+    assert claimed["_scheduled_instant"] is None
+
+    rows = executions.list_executions(job_id=jid)
+    completed = [r for r in rows if r["status"] == "completed"]
+    assert len(completed) == 2  # the on-time scheduled run + the manual run
+    manual_rows = [r for r in completed if r["source"] != "builtin"]
+    assert manual_rows and all(r["scheduled_instant"] is None for r in manual_rows)
+
+    assert completed_occurrence(get_job(jid), next_occurrence) is False
+    assert get_job(jid)["next_run_at"] == next_occurrence
+
+    # The next scheduled tick (tomorrow 19:00) must deliver, not dedupe-skip.
+    scan = _DueScan([get_job(jid)], datetime.fromisoformat(next_occurrence))
+    assert _evaluate_due_job(get_job(jid), scan, 3600.0) is True
+
+    # Symptom (a): a SECOND manual fire must still win instead of being refused
+    # as "Job is already being fired by the scheduler; not run again."
+    from cron.jobs import claim_job_for_fire
+
+    assert claim_job_for_fire(jid) is True
+
+
+def test_fire_webhook_before_next_occurrence_is_occurrence_free(temp_home, monkeypatch):
+    """Dashboard / NAS webhook fires (provider.claim_fire) arriving before the
+    next occurrence must not consume it either."""
+    from cron import executions, jobs
+    from cron.scheduler_provider import InProcessCronScheduler
+
+    job = jobs.create_job(prompt="x", schedule="0 19 * * *", name="evening")
+    jid = job["id"]
+    _simulate_last_scheduled_run(jid, monkeypatch)
+    _patch_now(monkeypatch, _midcycle_now(jid))
+
+    claimed = InProcessCronScheduler().claim_fire(jid)
+    assert claimed is not None
+    assert claimed["_scheduled_instant"] is None
+    row = executions.get_execution(claimed["execution_id"])
+    assert row is not None
+    assert row["scheduled_instant"] is None
+
+
+def test_ticker_keeps_occurrence_binding_when_firing_on_time(temp_home, monkeypatch):
+    """Invariant the fix must not weaken: a scheduled tick firing AT the stored
+    occurrence binds that exact instant (at-most-once per occurrence)."""
+    from cron import jobs
+    from cron.jobs import claim_job_for_fire, create_job, get_job
+    from cron.occurrences import scheduled_instant as canonical_instant
+
+    job = create_job(prompt="x", schedule="0 19 * * *", name="evening")
+    jid = job["id"]
+    next_run = get_job(jid)["next_run_at"]
+    instant = canonical_instant(next_run)
+    _patch_now(monkeypatch, datetime.fromisoformat(next_run) + timedelta(seconds=5))
+
+    claimed = claim_job_for_fire(jid, return_job=True)
+    assert isinstance(claimed, dict)
+    assert claimed["_scheduled_instant"] == instant
+
+
+def test_ticker_keeps_occurrence_binding_when_firing_late_in_catchup(temp_home, monkeypatch):
+    """A scheduled tick firing LATE (within the catch-up window, after the
+    stored instant) keeps the occurrence binding — the instant was genuinely due."""
+    from cron import jobs
+    from cron.jobs import claim_job_for_fire, create_job, get_job
+    from cron.occurrences import scheduled_instant as canonical_instant
+
+    job = create_job(prompt="x", schedule="0 19 * * *", name="evening")
+    jid = job["id"]
+    next_run = get_job(jid)["next_run_at"]
+    instant = canonical_instant(next_run)
+    _patch_now(monkeypatch, datetime.fromisoformat(next_run) + timedelta(minutes=90))
+
+    claimed = claim_job_for_fire(jid, return_job=True)
+    assert isinstance(claimed, dict)
+    assert claimed["_scheduled_instant"] == instant
+
+
+def test_forced_fire_stays_occurrence_free(temp_home, monkeypatch):
+    """force=True (Trigger-now / paused-job fire) is a manual fire by definition
+    and must never bind an occurrence (guards test_scheduled_occurrence's
+    "manual force is not a completion of the pending scheduled slot")."""
+    from cron import jobs
+    from cron.jobs import claim_job_for_fire, create_job, get_job, pause_job
+
+    job = create_job(prompt="x", schedule="0 19 * * *", name="paused-manual")
+    pause_job(job["id"])
+
+    claimed = claim_job_for_fire(job["id"], force=True, return_job=True)
+    assert isinstance(claimed, dict)
+    assert claimed["_scheduled_instant"] is None