Sorry I'm a little late to the party. It sounds like you found your issue. One thing I don't think was mentioned is the alignment of the gas tube. If your BCG doesn't align well with the tube it can cause malfunctions that mimic a gas problem. Well in all fairness it kind of is a gas problem.
I would go back out and shoot the thing and hopefully it won't happen again. Sometimes weird flukes happen.
I would go back out and shoot the thing and hopefully it won't happen again. Sometimes weird flukes happen.