Most servers upgraded, but needs reboot, and two nodes still 4.x (will be updated when possible). But I think error explained in topic start may be present in latest kernels too:
$ for h in {8,9,10,11a,11b,11c,11d,12a,12b,12c,12d}; do echo host$h; ssh root@host$h pveversion; done
host8...