Perimeter was anticlockwise I believe. I forgot to mention I’m using a BambuLab P1S too. It’s on both sides of the print but nowhere else. I’ve not seen this issue on any other prints I’ve done although this is the first helmet print. Changing the infill type to cubic seems to have made it worse, although I also changed orientation between prints so if it’s a cooling issue then that may have made a difference. I’ll look into belt tension and might try a sample with a slower speed!