The problems persist :(

This is another video for the long suffering Crystal, who is trying to help me find out why the machine is not operating properly.

I've done the auto-set up for the motors, and checked the ER wheels, cleaned them again, found a short piece of thread tangled around the inside hub, removed it, but it's made no difference to the performance.

Even moving in a straight line along the bottom of the pattern the machine is jerking forward and uneven in speed.