The way the battery is inserted may be a factor here, not just whether the battery is good or bad.
I ran into this problem yesterday after removing the battery (I was cleaning my screen with water and I think the instructions are to remove the battery). I removed and replaced the battery again and the problem isn't gone 100%, but it's much much better. So it's possible the battery is not bulging, it was just inserted in such a way that it pressed more against the inside of the machine. For me, it was very easy to turn the latch with a coin when the battery was in correctly.
This is with a late 2008 Macbook, which is on the tail end of its lifespan anyway.