[Runtime Bug]: Transformer RR weapon flickering in RTCW. Update: linked to legacyMaterial settings

Describe the bug

Running RTCW DX9 conversion, and using Transformer, flickers appear on the weapon when moving, it seems in low light conditions (speculation).
We have a Fallback distant light in the yard, no flickers appear there. But as soon as I enter the tower, or I move in front of the windows, weapon flickers. Also moving under some sphere lights in a hallway causes small flickers on the machinegun eyesight.

How do you reproduce the bug?

1. Copy Return to Castle Wolfenstein(2001)'s 'Main' folder to a new location.
2. Download Game DX9 binary from github https://github.com/whisperglen/RTCW-SP/actions/runs/13695698346 and unzip alongside game files (Main)
3. Get dxvk release from actions. I used dxvk-remix/actions/runs/13692493494
4. Need a bridge-remix that that integrates new RemixAPI headers (see rtx-remix/issues/736). I have my own build attached
   bridge-remix.zip
5. Create bridge.conf with exposeRemixApi = True
   ^^4 and 5 are needed for sphere lights to work, you can skip if too much trouble, but you won't see the flickers in the hallway mentioned above, and the game is very dark.
6. Add rtx.conf attached (please rename from .log, .conf files were not allowed)
   rtx.conf.log
7. Start the game, toggle console ~ and type "\spdevmap escape2"
8. Type in the console "\give all", select submachinegun and clear the big room ahead and to the right.
9. Sun is shining through the windows, turn your back to the windows and move around in the sunlight.
10. Go ahead through the hallway in your front and slight right, you should observe flicker on eyesight

What is the expected behavior?

No flickers on the weapon

Transformer:

CNN:

Video on Discord
https://discord.com/channels/1028444667789967381/1229858482530943037/1347663442940657787

Version

dxvk-remix/actions/runs/13692493494

Logs

No response

Crash dumps

No response

Media

No response

Start by reproducing the flicker with the listed DX9 and DXVK-Remix action builds, bridge-remix.zip, rtx.conf.log, and the \spdevmap escape2 and \give all console commands; also review rtx-remix issue 736 for the required RemixAPI bridge context. Done means the Transformer weapon and machinegun sight no longer flicker in the described sunlight and sphere-light areas.