diff --git a/plugins/platforms/photon/adapter.py b/plugins/platforms/photon/adapter.py
index efbf6fb288..3f1497f520 100644
--- a/plugins/platforms/photon/adapter.py
+++ b/plugins/platforms/photon/adapter.py
@@ -21,7 +21,7 @@ import sys
 import time
 from datetime import datetime, timezone
 from pathlib import Path
-from typing import TYPE_CHECKING, Any, Callable, Dict, List, Optional, Tuple
+from typing import TYPE_CHECKING, Any, AsyncIterator, Callable, Dict, List, Optional, Tuple
 from urllib.parse import urlparse
 
 if TYPE_CHECKING:  # type checkers see httpx as always-imported; runtime keeps it optional
@@ -86,6 +86,18 @@ _TARGET_NOT_ALLOWED_MESSAGE = (
     "targets — upgrade to a dedicated line or use another delivery channel")
 
 
+async def _aiter_ndjson_lines(response: Any) -> AsyncIterator[str]:
+    """Split the sidecar stream on its protocol delimiter, LF, and nothing else."""
+    pending = ""
+    async for chunk in response.aiter_text():
+        lines = (pending + chunk).split("\n")
+        pending = lines.pop()
+        for line in lines:
+            yield line
+    if pending:
+        yield pending
+
+
 # -- Sidecar runtime record ----------------------------------------------------
 
 def _runtime_record_path() -> Path:
@@ -621,7 +633,7 @@ class PhotonAdapter(BasePlatformAdapter):
                     if resp.status_code != 200:
                         raise RuntimeError(f"/inbound returned {resp.status_code}")
                     backoff = 1.0
-                    async for line in resp.aiter_lines():
+                    async for line in _aiter_ndjson_lines(resp):
                         if not self._inbound_running:
                             break
                         line = line.strip()
diff --git a/tests/plugins/platforms/photon/test_inbound.py b/tests/plugins/platforms/photon/test_inbound.py
index 0bee1d169c..c604158574 100644
--- a/tests/plugins/platforms/photon/test_inbound.py
+++ b/tests/plugins/platforms/photon/test_inbound.py
@@ -16,7 +16,7 @@ import pytest
 
 from gateway.config import Platform, PlatformConfig
 from gateway.platforms.event import MessageEvent, MessageType
-from plugins.platforms.photon.adapter import PhotonAdapter
+from plugins.platforms.photon.adapter import PhotonAdapter, _aiter_ndjson_lines
 
 
 def _make_adapter(monkeypatch: pytest.MonkeyPatch) -> PhotonAdapter:
@@ -150,6 +150,30 @@ async def test_on_inbound_line_dispatches_and_dedups(
     assert captured[0].text == "ping"
 
 
+@pytest.mark.asyncio
+async def test_ndjson_stream_preserves_unicode_line_separators(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    adapter = _make_adapter(monkeypatch)
+    captured = _capture(adapter, monkeypatch)
+    separated = "first\u2028second\u2029third\u0085fourth"
+    payloads = [
+        json.dumps(_dm_event(separated, msg_id="unicode-lines"), ensure_ascii=False),
+        json.dumps(_dm_event("ordinary", msg_id="ordinary-line")),
+    ]
+
+    class ChunkedResponse:
+        async def aiter_text(self):
+            stream = "\n".join(payloads) + "\n"
+            for chunk in (stream[:17], stream[17:43], stream[43:]):
+                yield chunk
+
+    async for line in _aiter_ndjson_lines(ChunkedResponse()):
+        await adapter._on_inbound_line(line)
+
+    assert [event.text for event in captured] == [separated, "ordinary"]
+
+
 def test_is_duplicate_window(monkeypatch: pytest.MonkeyPatch) -> None:
     adapter = _make_adapter(monkeypatch)
     assert adapter._dedup.is_duplicate("id-1") is False