The fast path trusted that marks matching the query case-insensitively
implied the set still covered every match. A stale mark from an earlier
query (raced re-wrap, external DOM writes) can pass that per-mark
comparison while live occurrences stay unwrapped — stepping then walks
old highlights and the new matches never light up. Gate the fast path on
a read-only coverage check (same skip rules as the walker) so any
unmarked occurrence forces a re-wrap.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Chen Jin
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