In fairness, distros do include their own patches, and it's possible that there is some regression that showed up somewhere above 6.12 and he's running a vanilla kernel and the Arch guys put in some patch that fixes whatever he's seeing that isn't in vanilla or something. Or maybe he's using a distro that includes some kind of kernel patch that introduces the problem, if he's not building his own kernels. I mean, I've got no idea what the guy is running; he doesn't say.