Forza Horizon 6 crashes with FHC01 after texture corruption and stutter (GTX 1060 / Pascal, Xid 13)

Software information

Forza Horizon 6 (Steam). Issue occurs at default/low settings alike:
frequent short stutters and texture corruption from the start; crossing
the bridge in the opening section crashes the game with error FHC01.
Kernel log shows NVRM: Xid (PCI:0000:23:00): 13, Graphics Exception at
crash time. The game renders and runs fine otherwise, so the fault looks
like accumulating resource/descriptor corruption rather than a startup
incompatibility. Reproduced across multiple Proton builds, fresh
prefixes, and two distros on this card.

System information

• GPU: GTX 1060 6 GB
• Driver: 580.178.04
• Wine version: Proton 9.x / Experimental / GE-Proton / Proton-CachyOS (all affected)
• VKD3D-Proton version: (bundled with each Proton above)
• Distro: CachyOS (also reproduced on BigLinux)

Other games (DX11 via DXVK, native Vulkan) run fine on the same system;
Pascal is capped at the 580.x driver branch, so fixes in newer branches
are unavailable here. Happy to test VKD3D_CONFIG options (single_queue,
etc.) or capture additional traces if useful.

Log files

Attached: steam-xxxxx.log with PROTON_LOG=1 captured across the FHC01
crash, plus dmesg/journalctl -k showing the full Xid 13 line(s) with
subtype.