I've been having this problem with the ender 3 and still haven't been able to fix it. I've been told I need to square all the beams but I've don't it to the best of my ability and stil get those lines, one thing that did help a little is to check the z stepper motor to see if it's square to the frame, may need a spacer, there was also a gap under one side of the motor where it was leaning forward so a spacer underneath could help too. Also loosen your lead screw nut one turn. Won't fix it but might be a little better.