Spotlight contribution shows ring/banding artifacts during slow 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 have a lower-confidence UE 5.5 repro where spotlight illumination appears to
show ring-like or band-like artifacts during slow camera movement.

Repro setup:

  1. UE 5.5 on Windows.
  2. Spotlight test map.
  3. Exact shadow/filtering settings from the attached conditions.json.
  4. Slow camera rotation while viewing the spotlight contribution.

Observed result:

The spotlight contribution has visible ring or stripe/band artifacts that
change with the camera.

Expected result:

The spotlight should remain smooth and stable during slow camera movement.

Evidence:

  • Attach evidence_sheets\07_聚光灯环状伪影.jpg.
  • Attach evidence_sheets\08_聚光灯条带伪影.jpg.

Question:

Has anyone seen spotlight rings/banding tied to shadow filtering or volumetric
settings in UE 5.5?

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_aligned.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.