doesn’t that conflict with the OP’s situation, though? there’s was set to enable rewind in the psx config (perhaps by accident but even so), and by reverting it they corrected the issue. so the individual core configs override the /all/retroarch.cfg?
if that’s the case I’m not entirely sure of the purpose of the all/ one!
video_threaded is set to false in all/retroarch.cfg (as of 3.0 final), so you could override that if my assumptions about overrides are correct. I’ve got an older version so it’s set to true. all my emulators work fine as far as I can tell.