Surfacing left small ridges

I finally got my Longmill 30x30 all set-up and mounted. Last night I surfaced my spoilboard using Gsender. When the router moved from left to right, it left an ever so slight ridge. When the router moved from right to left it did not leave any ridge. Everything on my machine is tight. Little to no play in anything. Any insights into fixing the issue?

I can’t quite picture in my mind the exact ridges you describe, but it really sounds like you need to tram your router/spindle. Basically the router is not perfectly perpendicular to the x and/or y plane. Search for Cnc tramming on you tube. Some good vids there, some with fancy calipers, some with simple tools. Your issue may not be related to tramming, but it would be good info to learn anyway.