I actually reported this issue to Bungie with a video when I found a way to freeze the game while replicating the glitch. I've been told by one of the BNGHelps that they sent it in for an investigation, so it might get fixed sometime in the near future. The suicide part of the glitch seems to mostly happen when the enemy's body or part of it despawns while you are performing a finisher on it. Either way, it always happens when they die or stop existing.