If it's a Chambers, and you haven't screwed with it, send it to Chambers and he will take care of the problem.
If a flintlock is fired, and the frizzen comes to rest on the flint, most of the times the frizzen has rebounded so fast you can't see it.
Check by opening the frizzen, put a thumb so you can just feel the front of the frizzen. **** and dry fire the lock. If you feel a tap on your thumb, you know the frizzen is simply rebounding.