We certainly can't fold to a <10% pot sized bet, just have to call turn and decide on river. One thing working in your favor is you bet quite large on the flop, so he might not have peeled with two pair, and it's hard for him to have JJ/77/22.

Your sizing in this hand is kind of weird. If you're going to 3bet OOP you generally want to go full pot. You're saying you're ahead of their range, so you probably want to pile in as much as possible while you're ahead, also lowering spr/reducing your positional disadvantage. Then on a flop texture this static I would usually start with a smaller bet. By betting the flop you're mostly representing a nut (maybe second nut) flush and you can still get stacks in over three streets with a small bet.

So, call turn...and soul read! Have a hard think about whether you know anything about this player that lets you interpret his oddly small turn bet sizing.

Just to throw out a theory, his bet might be inclined to find out if you have a full house since it's likely you will raise with it then just call.

Yeah i like erdians thought. This is a smaller flush a lot. I'd call, bet like 500 on the river, and fold to a shove. Whole hand would look weird at that point and I think he just pays off the medium sized bet.