Originally Posted by lurkingknight
v6 does it as well..
what happens is when you pull the trigger halfway or release partway through a cycle, it may stop the gears at a mechanical dead spot, either the battery/motor isn't strong enough to pull the gears off that spot, or the cutoff lever stops partway up, blocking the trigger block from moving to the fire position. By switching to full auto it usually pulls the cutoff lever out of the way so the trigger block can move.
Only real way to avoid it is pull the trigger fully and completely in semi, and don't release it until the firing cycle finishes.
that makes total sense. I very much appreciate the technical explanation.