Like others, first I’ve heard of a SAME tractor. RalphVa asked a good question. If there’s a clutch on the PTO shaft and it’s slipping it either needs adjusting or replacing. If it has a clutch on the PTO shaft, I would put witness marks on both sides of the clutch and recheck their alignment next time it does it. If the marks aren’t still aligned you know the clutch is slipping. You’ll need to follow the manufacturer instructions to adjust the clutch.
If there isn’t a clutch on the PTO shaft I have no clue.