UniversalRenderPipeline.SetUpscaler() with an unknown ID turns off the upscaler that was running

Steps to reproduce:
1. Create new Unity project using Universal 3D Template
2. Open Project Settings → Player → Other Settings → Scripting Define Symbols
3. Add ENABLE_UPSCALER_FRAMEWORK, press Apply and let Editor recompile
4. On PC_RPAsset.asset set Scaling Mode to Upscaling, Render Scale to 0.65, and add Spatial-Temporal Post-Processing to the Upscaler Priority list with the + button
5. Import provided “SetUpscalerRepro.cs” script to the project
6. Create GameObject in Hierarchy window and attach “SetUpscalerRepro.cs” script to it
7. Enter Play mode and read the Console

Actual results: SetUpscaler returns false and the active upscaler goes from unity.stp to none: the failed call switched off the upscaler that was running, and upscaling stops

Expected results: A failed SetUpscaler leaves the current upscaler alone

Reproducible with versions: 6000.7.0b1, 7000.0.0a1

Can’t test with versions: 6000.0.84f1, 6000.3.24f1, 6000.5.11f1, 6000.6.2f1, 6000.7.0a6 (Feature doesn’t exist)

Tested on (OS): macOS 26.6.1 (Apple silicon)

Notes:

•  nvidia.dlss4 is used as the missing ID because DLSS is not available on macOS: a realistic case of what a graphics-options menu would offer on unsupported hardware.