What was the reason for auto-assigning bounty to an unhelpful answer?

I posted a question on SO (here) regarding Windows app project management in Visual Studio. I anticipated that the question would be a tough one as I found nothing helpful when I was researching the issue before posting the question.

After the requisite waiting period, I posted a bounty of 100 rep to get some more attention. I had some interesting suggestions in the comments which I tried, but didn’t solve the problem. In the last 24 hours of the bounty, an answer was posted that went nowhere, and I commented on it within about an hour. But in a very short time it was upvoted twice.

I don’t understand why it was upvoted once, much less twice, as it seemed to me to be a stab in the dark. But, I went ahead and gave it a shot, and it was not successful, and I noted that in the comments on the answer.

Now that my bounty has expired, the SO system auto-assigned 50 of my rep to that answer because, according to the help docs, it had at least 2 upvotes.

I am confused as to why the 1/2-bounty was auto-assigned, and concerned that people that may be following up on the question will think that the answer was correct because the bounty is assigned to it. In truth, the person that was working with me in the question comments provided much more valuable advice than the answer did.

I am looking for help understanding why this auto-assign system is in place, and what is my recourse to draw attention to this question now that my initial bounty has expired.