Hi!   Has anyone found a solution to this problem? I am experiencing the same issue (see pictures).   I am using a modified Anet A8 printer, printing with 1.75mm PLA, slicing with Cura 3.6.0. I leveled the bed several times and increased the hot end temperature, but this did not solve the problem.   Since the under extrusion is (almost) perfectly periodic, I am thinking that this is a software fault rather than a hardware one.   Thanks!