It's now 18 months since this question was asked, and no real answer. I'm seeing the same message whenever I run an animation. the animation seems to work, visually at least, but this message is output to the log. It doesn't seem to matter whether the animation is to animate opacity or just move an entity via a transform. Every animation seems to trigger this output. I confess that I'm finding the entire experience of trying to move from SceneKit to RealityKit frustrating; simple things are far more complex to implement, and far more obscure. The documentation is lacking and not up to standard, especially given the time Apple has had to flesh out RealityKit and decide to deprecate SceneKit.

It turns out that the issue is memory related. I found an old Apple TV (and original devkit) on which the issue occurs. The app is exhausting memory at start up. So I have some sleuthing to do.

Thanks for that suggestion. I've been watching that space avidly. Nothing showing up thus far.

I have submitted feedback for the same issue.

I loved this idea of using the black sprite node however it still presented issues for me when transitioning between two "scenes" that contain SKTileMapNodes. So what I do is have a wrapper node that is a subclass of SKSpriteNode. When I want a tiled background, I create an instance of this class that internally creates an SKTileMapNode that is never actually presented. Once that SKTileMapNode is created, I then create a texture from it and initialise my wrapper object using that texture. From then on, it is a simple SKSpriteNode that obeys the alpha like all good SpriteKit nodes should, and I don't have to do any fiddles with black nodes. p.s. I can't believe (though I should by now) that Apple have not been able to bring themselves to fix this after 6 years.