[Wada]

Your check on the turn could be inducing a bluff. When you say 95% he's betting a weak ace here, you are forgetting all the other times he's betting a smaller PP or taking a stab at it with a missed draw. This is such a scary board that even the board plays itself that it makes some people feel that they can bet at it knowning it might be a chop but putting pressure on you to fold without having to risk much.

The turn check indicates weakness and his bet into two players indicates strength which is what he might try to imply, thus making a bluff and will auto fold if raised.

Way too weak tight imo to be folding the river after checking the turn, especially when you have a shot at winning and having 6.5 to 1.