Although i havent experienced a snake not eating prey from a different supplier or bag, i have read that it can happen. And considering how finicky BPs can be, its not out of the realm of possibility.
However, at that age, and this time of year, I'd chalk it up to coincidence. He's likely more concerned with finding a mate. I would offer every 2 weeks (or even longer) until he eats. You'll likely find he'll start up again in a few months and won't look back...for a while...