I've had a few bad bottles of beer over the years, but I don't think I've had a single skunky beer in a brown bottle that wasn't mishandled, or at least that I chaulked up to a friend mishandling. Tonight the first beer from a 12 pack of very reputable beer was way off. I was prepared to take it back, but number 2 was excellent. This is a normal favorite and the bottle date is very recent. I'm defintely not going to worrry about one bad bottle out of 12, but would probably go back if I find more. Mostly curious if this happens more than I realize.
brown bottles will not always protect from everything if they are not stored properly... you should email the brewery about the bottles you purchased