I'm gonna take a shot to hopefully draw some attention.
First I'm gonna say get a little more descriptive in the problem.
However, with what I can make out you said adapter, is something like these?
https://www.google.com/search?q=li+...UoAQ#safe=off&tbm=isch&q=510+adapter&imgdii=_
What I would could say the problem is is that the little rubber sleeve that runs along the positive pin getting crushed and causing a short.
For the leaking you may have a broken O-ring.
But again try to describe the problem in the fullest detail.