What should I do if I have commented on a bounty'd question asking for more information, the OP has not responded, and the bounty is about to run out?
Background for this specific question: The OP lists two problems in their question: GitHub shows too many commits to be merged, and the Merge button doesn't work. After some edits, it was clear why the extra commits show up (but not why the OP would expect otherwise, or why this hasn't happened before), but there was no indication of why the Merge button would not work. I commented asking for more information, and the OP has not yet responded.
All that to say: there is not enough information to provide a good answer to the question. There are 3 current answers, all of which say little more than "you should do a manual merge, and here's some debugging you can do".
I suspect that the ideal solution would have involved closing the question as lacking an MCVE until the OP has provided this information. However, given the state of the SO Close Vote Queue, it's not likely that it would have been closed before the bounty was added. (And since the bounty was added so quickly, I wouldn't have had the chance to ask for help closing the question in chat.)
What should I do instead? Should I provide an incomplete answer (as other users have)? Does the fact that this question has a bounty (and the bounty is about to expire) change anything?