2nd to last tray, lower teeth not straight but tray is straight

I have a pretty short plan only 16 trays.

I’m on 15 right now. I looked at my lower teeth and noticed that they are not straight. Slight rotation, slight crookedness.

It made me concerned because this is my 2nd to last tray. And the thing is, if I just look at the tray out of my mouth, it looks perfectly straight. Yet my teeth aren’t, but the tray also fits on without any noticeably concerning gaps or anything.

Is this common? Or something I did wrong? I feel as if I have been quite decent at my wear time. Also, because every tray fit on snugly, and there were no obvious signs of not tracking, I assumed everything was going as expected.

I know refinements are common, but it kinda sucks I’ll have to rescan and wait another month for those.