I’m resurfacing my spoilboard but getting grooves or lines leaving deeper cuts as shown. I painstakingly leveled my z axis over and over again but is this something different I’m doing or missing?
This looks like your router might tramming to ensure it’s level in all directions.
I don’t know if this video is any good, I just found it searching. You might want to search for yourself to see if anything is better if that doesn’t work.