I'll keep an eye out on upstream and try the master branch in RR with 5.12/13/14 and report back.
I've tried building from SupervisedThinking/master-rr-westmere which is running media-driver 21.3.1 and mesa 21.2.1 but no luck, same issue.
Also tried updating kernel to 5.12.19 but I ran into a bunch of issues with the packages. Fixed some but got stuck on getting crazycat to build.