I had a phone screen with the hiring manager, which went well. Then I came in for an interview with several people from test and a developer. That also went well.

They told me at the time they couldn't quite meet my salary request, but made it sound like they would do their best to come close.

So, they asked me to come in a third time to speak with a more senior developer. That was the only moderately challenging interview I had.

The next day, they called me with the most ridiculously lowball offer I'd ever heard. Including stock, it was less than I'd been making as a base salary 10 years prior, and about 30% less than I was asking – which was already lower than my previous job's salary.

They claimed this was the best they could offer in the East Bay. This is incorrect, as I currently hold the same role less than five minutes from their office and am making significantly more.

I wouldn't have minded the low offer if they hadn't called me back in and wasted my time when they clearly had no intention of meeting my salary expectations. The offer was insultingly low.

If you have a range of builds where a bug might have occurred, what's the most efficient way to determine where it did occur?