High-frequency stripe material shimmers and destabilizes nearby reflections

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 know some shimmer is expected from extreme high-frequency materials, but I am
seeing a stronger artifact in UE 5.5: the stripe material shimmers and nearby
reflective/glossy content also flickers.

Repro setup:

  1. UE 5.5 on Windows.
  2. High-frequency black/white stripe material.
  3. TAA or TSR enabled.
  4. Screen percentage in the captured cases includes values such as 50, 67, and
    75.
  5. Slowly translate or rotate the camera while the striped material and nearby
    reflective object are visible.

Observed result:

The stripe pattern shimmers/moire-flickers. In the stronger captures, nearby
reflective or glossy surfaces flicker too, so the instability is not confined to
the material itself.

Expected result:

The temporal AA result should be as stable as possible, and reflected/glossy
neighbors should not abruptly flicker due to nearby high-frequency material.

Evidence:

  • Attach evidence_sheets\10_高频纹理导致周围可反射物体出现闪烁.jpg.
  • Attach evidence_sheets\09_高频纹理抗锯齿效果不及预期.jpg.
  • Attach the material setup and screen percentage.

Question:

Is there a recommended way to stabilize this beyond texture mip/UV changes? Has
anyone seen high-frequency material instability propagate into reflections?

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.