[Shilly]

Well, it was unraised preflop, so there's a lot of possibilites here.

1)BB has a higher flush: Somewhat consistent with flop action. Doesn't need to protect hand on the flop (especially if he has the nut flush) against another spade on the turn. However, his turn bet is awkwardly large.

2)BB has a lower flush: Not very consistent with the flop action. He probably would have raised to protect his hand from a higher spade draw. He makes a big bet on the turn to protect his hand.

3)BB has a pair value hand/two pair/set: He could have a weak two pair holding like T4, and wants to peel off a cheap card on the flop and re-evaluate the turn. After the turn bricks, he snaps into action with what he thinks is the best hand and tries to protect it.

Tough hand, but I think I'd push here. The deciding factor for me is his strange turn raise. It doesn't really seem to fit the profile of a hand that beats you.