Problem with constant velocity?

Hi all, I'm hoping somebody can point me in the right direction, and I'll apologise now for spamming the board as I've got a few questions lined up for this evening  below are a couple of images of a test cut I did today and most of the file came out perfect but there was an area on a cross it decided to go rogue and do it's own thing, I thought it was perhaps something to do with the Sheetcam software so I reached out to them for advice and they mentioned it was something called "Constant Velocity" that was enabled ??

Could anybody advise as to how I disable "Constant Velocity"?

This is linuxcnc 2.8.2

Thanks in advance, kindest regards
Rich

Worked a treat, thank you so much!