Light/volumetric contribution flickers during camera movement

Context: this report comes from a RenderFuzz-based UE 5.5 rendering anomaly study. I am posting the issue publicly so other Unreal Engine developers can check whether it is reproducible, already known, or has a practical workaround.

I am seeing light or volumetric contribution flicker during camera movement in
some UE 5.5 captures. The current cases often involve volumetric fog and FXAA,
but I am still narrowing the exact dependency.

Repro setup:

  1. UE 5.5 on Windows.
  2. Light/volumetric test map.
  3. Settings from the attached conditions.json, including volumetric fog in
    the captured cases.
  4. Move the camera using the included path.

Observed result:

The light source or surrounding lit/volumetric region pulses/flickers as the
camera moves.

Expected result:

Lighting and volumetric contribution should remain stable under camera movement
when the light/fog settings are not animated.

Evidence:

  • Attach evidence_sheets\29_视角移动时光源闪烁.jpg.
  • Attach representative video and exact settings.

Question:

Does this look like a known volumetric-fog temporal issue, or should I isolate
FXAA/ray-traced shadows/screen percentage first?

I also submitted this through the Unreal Engine Bug Submission Form and am using this thread to keep a public reproduction record.

Attachment note: I attempted to attach video_comparison.mp4 here, but this forum account is currently blocked by the forum’s new-user attachment restriction. The representative video was attached to the Unreal Engine Bug Submission Form submission and can be provided again when the forum allows attachments.