Crash in sl_interposer during D3D12 init on RTX 5070 (Oblivion Remastered, UE 5.3.2) — only fixed by fully disabling interposer

Summary

Consistent crash on launch of The Elder Scrolls IV: Oblivion Remastered (Steam AppID 2623190, UE 5.3.2-237883+Release, BuildVersion 1.512.105.0) on an RTX 5070. The crash originates inside Streamline's interposer while it's hooking into D3D12, not in game code.

Environment

• GPU: NVIDIA GeForce RTX 5070
• Driver (Windows WDDM version string): 32.0.15.9186
• Engine: UE 5.3.2-237883+Release
• Game build: 1.512.105.0
• Streamline plugins present in the title: sl.common.dll, sl.dlss_g.dll, sl.pcl.dll, sl.reflex.dll, sl.deepdvc.dll, nvngx_dlssg.dll, nvngx_deepdvc.dll

Crash callstack (from UE's CrashReportClient, GetContextStackTrace)

Faults in KERNELBASE, called through this chain (top-most frames first, abbreviated):

KERNELBASE
OblivionRemastered_Win64_Shipping
ucrtbase (x6)
ntdll (x3)
KERNELBASE
VCRUNTIME140
sl_interposer (x4)
VCRUNTIME140
ntdll (x3)
nvwgf2umx (x8)
D3D12Core (x2)
<dynamically-loaded unnamed module, e.g. 1B0_E658703_7ff8675c0000> (x4)
sl_interposer (x2)
OblivionRemastered_Win64_Shipping (x10)
kernel32
ntdll

This exact signature reproduced across multiple independent crash reports (different minidump hashes, e.g. UECC-Windows-CDF28AFB452F95D1E7146A85AF862255_0000 and UECC-Windows-1EE7599A47116F5608ED108C60A03ADD_0000), always with the same module sequence: sl_interposer → an unnamed dynamically-loaded module → D3D12Core → nvwgf2umx (NVIDIA's D3D12 UMD).

What was tried

1. Renaming sl.pcl.dll → sl.pcl.dll.disabled (a fix suggested in community threads for this game). This was not sufficient — the game still crashed with the identical sl_interposer/nvwgf2umx callstack shape on the very next launch attempt (new crash hash, same structure).
2. Renaming sl.interposer.dll → sl.interposer.dll.disabled (disabling the Streamline interposer entirely, not just one plugin DLL). This resolved the crash — the game now launches successfully. This obviously also disables DLSS/Frame Generation/Reflex entirely, which isn't a real fix, just confirms where the fault lies.

Notes

• Other RTX 5070 owners are reporting similar frequent crashes for this title in the game's own Steam Community discussions, with one user noting fewer crashes on an older RTX 3060 with the same game version — suggesting this may be specific to newer/50-series hardware interacting with whatever Streamline SDK version is bundled with this title.
• I don't have the exact bundled Streamline SDK version to hand (game ships prebuilt DLLs, no version manifest found alongside them), but can pull file version info from sl.interposer.dll etc. if useful for triage.
• Happy to provide the full minidump (UEMinidump.dmp) or CrashReportClient.log if that would help narrow down the interposer-side fault.

Filing here since the fault is inside sl_interposer.dll itself (not the game's own code), and this may affect other titles using Streamline on RTX 50-series hardware.

No source file or test is named. Start by reviewing the interposer's D3D12 hooking path and reproducing the crash with the provided callstack, minidump, or CrashReportClient.log; compare behavior with sl.interposer.dll enabled and disabled. Done requires a confirmed root cause and a tested fix that allows the game to launch without disabling Streamline features.