PREFLOP: I'm not a fan of raising this type of hand UTG. I prefer to limp and play it for its set value or fold if the game is too tough.

FLOP & TURN: Standard

RIVER: There are 3 flush cards and 4 to a straight on the board. It could be a situation where the BB had a flush or turned a straight but decided not to get aggressive fearing you wouldnt call if you had AK. This could easily be the case. I find that HU when people check and call every street and then bet the river they usually have a monster or total air.

That said, It could also be the case that the river ace made the BB top pair or two pair and hes betting cuz he knows you dont have the straight and you are unlikely to have the flush.

I think raising this river is ok, but it is pretty thin considering how passive the villain is. I think the river is very close between just calling and raising with the intention of calling a 3 bet. I think I would raise, and once 3 bet I would cry and call. I think capping here is clearly wrong.