So I have another spot I'm confused about why the solver is doing what it's doing

Situation is K67ssx BTN vs BB, we c-bet 55% BB calls.

Sizings on the turn are 150%, 85% and 55%. We're doing a lot of overbetting here.

On the As we're doing no overbetting, despite this being a better card for our range than the Qs. Why is this the case? My only guess was that villain was check raising more Axss than Qxss so he gets here with more nut flushes, but that doesn't seem to be the case as a lot of Axss are still just calling. Any thoughts would be much appreciated