Same here, iPhone Xr(iOS15.0.1), pixijs wkwebview , background then foreground everything frozen(not 100%, keep trying for a few times you’ll trigger this). After some investigation, I find changing canvas size and some other operations takes too long to perform which is the cause of frozen. Operations like fillText & fillRect not working at all, canvas data url stay the same as before.

Is this report answered? Seems I don’t have the permission to view it. Will you please comments here if got any official solution? Thanks a million!

And disable GPU Process: canvas rendering not help, can still reproduce in 15.0 simulator, in my iPhone Xr(iOS 15.0.1) this bug too hard to reproduce, so I can't tell is it really fixed or just bad luck.