I am seeing the same thing. I created a ShaderGraphMaterial that has transparency, and applied it to a sphere. Then added a spherical particle system around it. The particles in front of the sphere flicker on and off.

Ok, it happened again today. I really have no idea what causes it to start happening. It appears random. Sometimes everything is working perfectly well, but then it gets into a state where it stops reporting mesh updates. I attempted to capture my syslog around the time I noticed it start happening. It is feedback FB13808797.

My code was set up following that sample code, and doesn't deviate from it very much at all, other than the type of mesh it creates. Can you point me to how to trigger the sysdiagnose? I tried accessing this resource from another forum post, but it says I don't have access even though I am logged into my developer account: https://download.developer.apple.com/visionOS/visionOS_Logs/Sysdiagnose_Logging_Instructions.pdf

I also had this same issue yesterday.

It appears that this setting is only valid for devices that have iOS 14 installed. I also was getting the failure to install, but after updating my iPad Pro to iOS 14, it now is able to install via XCode.