It looks like the rendering problem occurs when the value of the "Compositing Mode" parameter is set to "Standard".
That setting has been removed in the latest beta because, ironically, it actually tends to cause more bugs when set to "low latency".
Graphics driver bugs are a nightmare to deal with. Try to get in touch with AMD if you can, otherwise try filing an issue with Google to see if they can help. Maybe also turning on/off WebGPU mode will help avoid the issue.