I was using the Polaris Lance to complete bounties and have noticed that some of my perfect 5th shots are not exploding. After testing a little bit in the tribute hall, I found out that the perfect 5th shot disappears if you shot again before it explodes. The fallow upshot doesn't have to be on target for the perfect 5th shot to disappear. I play on the ps4 and wonder if this is happening to anyone else?