Clearing color occurs on specific camera setup

I got specific camera setup in my project. Gameplay scenes have HDR camera each which also use custom post process via render feature that resolves HDR render buffer into camera color target.
Then I have a persistent scene with UI Camera which has HDR rendering disabled and Background Type: Uninitialized.
While in Editor everything works as intended, on Android builds UI Camera rendering starts with Clear (depth+stencil+color).
Is there a simple way to prevent clearing color on UI camera, without radically chaning camera setup?