Flat spot on start, on engraving round logos

I am wondering if anyone has run into the issue where their round logos or engraving have a flat spot right at the very start. It does other rounds well, (see pic) the inside round is perfect but just the star is flat. I am wondering what on earth could cause this. I am using lightburn and a piburn rotary. I increased y accel and nothing seems to make a difference. Can someone tell me what it could possible be.

How are you engraving this? It looks like the scan lines go ‘around’ the mug…?

Is it only that side of the mug?

I have a PiBurn V3 but it’s on my co2 laser.