If you are releasing your windup too early you might have gotten comfortable on smaller spins "winding up too early" and it's only showing up now. See how crisp and snappy your 3s get if you wait longer to windup, like literally just past the start of the transition. If you are getting 90 on your setup carve, you are probably also starting that too early and making it too big which can easily be masked in 3s etc. and is probably just showing up now.
Check out Nev Lapwood here in his "Advanced Spinnning" vid:
Advanced Spinning Part 2 (Regular) on Vimeo
You might think you are leaving the lip straight but obviously your friends are telling you that you're not. It's like everything we always think our legs are bent more than they are or that we are flattening the board in the pipe more than we are etc.