Alright, I may have a lead on this issue.
@dominic.ermark , @xaver.freiherr-loeffelhol : Can you please check what the Tracking Origin Mode is set to?
- Hierarchy > Select XR Origin
- Inspector > XR Origin > Tracking Origin Mode > dropdown
If it is NOT set to “Floor”, could you try this with the reprojection shader enabled, and see if the issue recurs?