That's weird. I mean it's hard to track the reason since the system is rather complex. Could you try to get out of the range and try to target lock again? I never got into such problem during hundreds of tests.
No matter what I did I couldn't get it to target lock again. I even tried leaving the room the boss is in and going back in and nothing. I'm not sure what caused it, I can't think of anything strange that I was doing when it happened.
yeah...let's just leave it there. What I want to know is if this problem consistently happening? I mean if it's happened everytime you play the game then there must be something which make it like that.