Wavy Raft

Struggling with Cetus 3D printing a Wavy raft. Once it gets to print the object it seems ok … (less neat than when I first purchased but acceptable )
This has only just randomly started happening. It also seems to struggle to print the first layers, before the horizontal wavy layers.

I have recalibrated it several times, and doesn’t seem to solve the problem, I have a 2nd Cetus machine that doesn’t experience any of this.
Any advice…