Is there a reliable way to detect if a browser will have this problem, and so turn antialiasing off conditionally?
You would need to probe the user agent and detect that it is a 15.4 version then maybe the webgl debug info would let you know if it is M1 or not but I do not think so… Fortunately I hope they will fix it soon as it looks like it might already be top of tree on webkit
Thanks! We’ll do that for now. Hope the webkit fix will come out soon
Folks on bugzilla are confirming this is fixed for next release 
YES! Can’t wait for the update now 
I just came here to confirm that our users are seeing the same issue and that the Webkit team marked the issue “fixed”
Any idea how new Safari versions are rolled out?
I wish I would but unfortunately nope 
Apparently, 15.4.1 rolled out but users are still seeing the bug.
yup I do not think the fix was put in it
This is just a general question, but do you guys have a way to run visual regression tests against upcoming Safari versions? I think they broke WebGL about a year ago as well. Just wondering if there’s a way we can catch these before they are released.
I guess no one on the Webkit team realizes how cool 3D is 
cc @RaananW
To be fair; did catch/report this one before it released. Did not stop them from releasing though 
Let he who has never released a bug cast the first stone 
The webkit team seems to have fixed it. Just updated to iOS 15.5 and all the issues we had are gone.
webkit: webkit bug report
Safari Update 15.5: WebGL issues fixed
WebGL
Resolved Issues
- Fixed WebGL rendering when using
preserveDrawingBufferon iOS.- Fixed a number of issues related to multisampling that were breaking WebGL content.