Master controller Issue.

I’m creating my first head Master Controller. Ive followed all the instructions provided in this tutorial, https://www.youtube.com/watch?v=Tbp95snCPr4&ab_channel=Oli and it almost works perfectly. In the character’s default position, the rig works fine, everything tweens like it should. My issues start when I turn the head using the controller after I’ve adjusted a deformer.

If I transform a drawing (say I move an eyelid down) it rotates and tweens fine, however if I adjust a spline deformer and then try to use the master controller to turn the head, the changes I made to the deformer don’t turn like they show in the video at 11:17. Instead they just snap back to their default positions once I adjust the master controller. If i adjust envelope deformers its a similar problem, if I adjust any envelope deformers (like the shape of the hair) and then move the master controller, the points of the envelope deformer snap back to their default positions, but the orientation of the bezier handles stays. Here’s a link to a video of my issues, any and all advice is welcome!

My Issues Vid: https://youtu.be/vR48_BhaknY
Tutorial I followed: https://www.youtube.com/watch?v=Tbp95snCPr4&ab_channel=Oli