That's bizarre, but the pot is small so I don't think your decision here really matters a whole lot. I'd probably just fold and move on to the next hand.

If he was interested in bluffing, I'm not sure why he would decide to show weakness on the flop, then make a weak bluff on the turn. It's also somewhat suspicious how he checked the flop to begin with, given that you say he's "tight aggressive." Does he not make continuation bets? It's possible he may've flopped a set (perhaps 7-7), attempted to trap you, and is now betting out for information since he's concerned over the 4 card straight. This is just speculation, though.