Swift 6 (not Swift 5) hits a breakpoint in libdispatch.dylib

My app has 2 targets, iOS and visionOS. It uses some Metal code for rendering.
If I compile it with Swift 5, rendering works as expected.
With Swift 6, rendering hits unexpectedly an internal breakpoint:

This happens for iOS and visionOS, for the simulators and the devices.
Apparently, code that is executed to run on a certain queue is executed on another queue. The only queue related to Metal in my code is a MTLCommandQueue.
I guess this is a bug in the library, but I am of course not sure.
Is there anything I can do to get the code running?

I found the instruction that does not work under Swift 6 (I should have done this earlier, sorry).

My app uses a PerspectiveCamera in a RealityKit entity.
Currently there is bug in RealityKit (confirmed by Apple) that does not allow to use the output of an additional PerspectiveCamera directly. Instead, one has to use a RealityRenderer.
To its property entities, a PerspectiveCamera can be appended. Its output is rendered to a MTLTexture. It can be assigned to the metalLayer of a UIKit UIView, which is then displayed as a UIViewRepresentable in SwiftUI.

A RealityRenderer has a function updateAndRender that renders its entities including the output of a PerspectiveCamera, see here.

This function works under Swift 5, but hits the internal breakpoint under Swift 6, before the handler onComplete is called.

So I guess this is a bug in RealityKit, and I will write a bug report.