Not quite sure if this should go to Steam's issues or Proton so I'm creating it here as it seems to be more relevant.

System Information:

• AppID: 3314070
• Proton: 1774341903 experimental-10.0-20260324 (switching to Proton 10 or 9 had no effect on the issue)
• System: Fedora 44, kernel 6.19.11-300.fc44.x86_64, Mesa 26.0.3
• GPU: Radeon 680M (integrated on Ryzen 7 PRO 6850U) - AMD Radeon Graphics (radeonsi, rembrandt, ACO, DRM 3.64, 6.19.11-300.fc44.x86_64)
• Desktop: KDE Plasma Desktop 6.6.3, kwin 6.6.3, sddm 0.21

Issue:
With shader pre-caching in Steam enabled, the game (The Sims 2 Legacy Collection) takes upwards of a whole minute to even start and pretty much 9 out of 10 times immediately crashes; interestingly, there doesn't seem to be any issue with the game once it manages to actually start once. Game starts quickly and loads correctly pretty much always with pre-caching disabled.

Nothing other than disabling the shader pre-caching fixes the issue; I've tried dropping gamescope (unrelated to the current issue but the game ran on its own also has this problem of constantly grabbing focus at a frequency at least more than every second, which has been for a few months but the game started off okay; not fixed by going back to older version of Proton either), dropping the Wine DLL overrides for the ASI loader, and just a variety of random Proton/DXVK configurations with the exception of switching to WineD3D.

Judging by the logging, the point of failure seems to be in Mesa's Vulkan drivers; could it be that Steam is getting invalid compiled shaders for the configuration somehow? There are several reports on ProtonDB suggesting that WineD3D should be used instead of DXVK, and I also wonder if that would be related to this.

Relevant bit of log:

info:  Found device: AMD Radeon Graphics (RADV REMBRANDT) (radv 26.0.3)
info:  Found device: llvmpipe (LLVM 22.1.0, 256 bits) (llvmpipe 26.0.3)
info:    Skipping: Software driver
80794.524:0130:0134:trace:seh:handle_syscall_fault code=c0000005 flags=0 addr=0xdf6085a0 ip=df6085a0
80794.524:0130:0134:trace:seh:handle_syscall_fault  info[0]=00000000
80794.524:0130:0134:trace:seh:handle_syscall_fault  info[1]=deaab02c
80794.524:0130:0134:trace:seh:handle_syscall_fault  eax=000d3344 ebx=e04523a0 ecx=000d4000 edx=0001199b esi=deaab028 edi=f2df6148
80794.524:0130:0134:trace:seh:handle_syscall_fault  ebp=e04523a0 esp=0143f8e0 cs=0023 ds=002b es=002b fs=0063 gs=006b flags=00210216
80794.524:0130:0134:warn:seh:handle_syscall_fault backtrace: --- Exception 0xc0000005 at 0xdf6085a0: /run/host/usr/lib/dri-freeworld/libvulkan_radeon.so + 0x32f5a0.
80794.524:0130:0134:trace:seh:handle_syscall_fault returning to user mode ip=77b3ff53 ret=c0000005
80794.524:0130:0134:err:msvcrt:_wassert (L"!status",L"../src-wine/dlls/winevulkan/loader.c",392)