I think this hand pretty much plays standard up until the turn. Pre-flop I do think this is a potential 4-bet bluffing candidate against Villains who 3-bet light. Since the CO was unknown, I obted for a passive defend in game.

The CO's flop checkback considerably caps his range in my opinion, as I expect pretty much all overpairs and FDs to barrel here. Although in theory, the IP player is expected to play pretty passively on a board like 654ss as discussed in this thread yesterday, I don't expect this play in my NL10 pool though. I thought this is a nice spot to double barrel vs. his checkback range that should be predominantly composed of Ace high-type hands that should find a fold even on this type of runout. Agreed?