People keep discounting the backdoor flush, but I don't think it's as unlikely as people say - precisely because of the stack sizes.
If UTG has a
[Jc]/[Ac][Tc] type of hand - the flop raise and c-bet are standard. After OP raises the c-bet, the stack sizes come into play -
With 100BB effective stacks, it's a pretty easy fold with 2 overcards and a BDFD - the raise is 25% of the stacks..
With 250BB effective stacks, calling the raise commits less than 10% of your stack - UTG can call with a much wider range here.
On the turn he picks up his flush draw - he needs to call $860 with $1890 already in the pot and $3500 behind - again, it's close, but I think he has the implied odds to call here.
And once he hits his flush on the river, he's just thinking about how to get all his chips in the middle.
And don't forget - there was a 25/50 game yesterday where someone stacked off 600BB with unimproved Aces, so it wouldn't be unheard of for villain to show down less than a better FH here.