Overpairs can be tricky in that way. You're holding aces, you 3-bet OOP, the initial raiser calls you. Fair to bet their range includes A-Broadway, Pocket Pairs, maybe some lower suited connecters depending on the player.
So you get a flop like T 6 7 with a couple matching suits on the board. Most of the time you're ahead here but what if your opponent starts playing back at you, making value-ish moves, check raises you on the turn? Now you have to start questioning how aggressively your opponent will play two pair, top pair, what is the likelihood they're overplaying a draw or semi-bluffing? And ultimately you have to follow your gut and try to make the play that you feel is most-likely to be correct, because you will rarely know for sure.