Valve's out of spec

or everything is wearing BUT the valves and seat- cam/follower/shim- my valve adjustments got loose on my KTM right before the rocker roller bearing (kinda like the follower on husky) went to pieces...
But as Rajobigguy stated - the valves probably seated from initial setting- now they most likely will be stable for a long time. Just check them periodically to verify they are in spec.