I agree it dosent need pinch at top (auctual piston locking on top of sleeve) just causes friction which makes extra heat,
what i should have said is it dose not hold compression at tdc
motor out of car ,hold it by flywheel and set the head at a 45dag angle and it will blead compression and roll over so head is pointing straight down in about 1-2 seconds,

Ill give it a snugging up with the old pincher if it acts up this weekend(very light snugging)