HorizonOS v81 update broke Passthrough in startup Splash Screens

Hi folks,

This is for a project in a C++ UE 5.5.3-0+oculus-5.5.3-release-1.109.0-v77.0 engine from official Oculus Branch.

A recent update to Horizon OS, likely v81, seems to have changed the way Splash screens are handled to now send the user to a black void with particles and wisps flying by. This has created a big problem for our MR application in that now NO Passthrough is visible during splash, which is causing us to fail VRC (Functional.14). This was not an issue before this OS update.

These are the settings and image (PNG with transparency) we are using:

Even forcing bAutoEnabled to True in DefaultEngine.ini does not help:

Setting to Black also gives the same result, which is the black void with a very low resolution proxy of the PNG we have: 

For reference, this was the behavior before the v81 update:

We also scouted other MR apps and it seems they face similar situations (?)

Any help is appreciated as we'd rather not request any waivers during our QA process.

Thank you!

-Sebastian