It is if the broadhead hits the shelf before the rest stands up... it will literally pull the nock off the string. I've also had my arrows cut too short where they would hit the rest at full draw and pop it off (In both cases I was probably using an old arrow on a new bow setup - and didn't actually cut them that short on purpose). If there's a way to do it wrong, I've probably been there done that... hopefully only once though. Rests that can be locked in the up position while drawing eliminate the first issue.
DC
