I have been running into this exact same issue with my latest prints using Cura 5 and 5.1beta. It has happened on parts of my models as well, specifically when printing circular forms such as screw/bolt holes in models. The outer perimeter will print, then the nozzle will backtrack 1-2mm, and then start the next line. I have never experienced this in previous versions of Cura, and I'm here hoping that someone might have an answer. Last time I had an issue that didn't seem to have a common or easily solvable fix, it was a hidden setting in the new version of Cura.
If anyone discovers the mussed setting, or a way to prevent this new "lurch/backstep" from happening, I would be very appreciative.