Don;t have a solution but have the same problem. I create a scene in RealityComposer, export to USDZ and load using ARkit The RealityComposer has a circular Logo (as png) in the background with transparent edge. Was working until recently - so maybe IOS 18 /Xcode or Arkit is breaking it. I also notices that addGestures is flaky if the image is included in the scene.

I tried ARCapture today and it works very nicely. It also appears to support occlusion also.... nice job !

ARVideoKit is excellent but it has one omission - People occlusions are not recorded in the AR view so people passing behind objects is not recorded properly....