I took a quick look through v6.1..v6.3.1 there is a patch that I think is the likely fix, it first landed in v6.2
1cf26c3d2c4c apparmor: fix apparmor mediating locking non-fs unix sockets it matches up the reported audit logs. Unfortunately it does not have a Fixes tag but as best I can figure it should be applied all the way back to. 56974a6fcfef apparmor: add base infastructure for socket mediation how/where this bug surfaces partly depends on the userspace policy and compiler which combines the features set supported by the kernel with what policy claims to support. So it is possible to have an affected kernel but not trigger the bug.