Yeah, yeah. This bug has been reported several times before. But this time I have proof.
Mostly noticeable with the Anigua, it's quite bothersome when this happens. Could this be with misaligned hit-boxes, or the hitbox doesn't exist at all until the end? Whatever the case may be, it only happens on certain angles the player/bullet is facing. For this instance facing the left.

http://img40.imageshack.us/img40/376/spiral20110413111549.png
http://img18.imageshack.us/img18/6264/spiral20110413111541.png
http://img607.imageshack.us/img607/7705/spiral20110413104757.png
http://img825.imageshack.us/img825/6189/spiral20110413104747.png

I'm thinking that the antigua's bullets don't even HAVE a hitbox up close, moreover on a certain angle, and their hitbox only active during when it disappears. Take into account the last two screenshots with this statement.