These "skips" can start in the middle of a line. It always comes back and fills them in before starting the next layer - more or less accurately. But from my very limited understanding of gcode, it doesn't seem like this should happen.
When watching the print closely, I'll occasionally see small glitches, where the head jogs very slightly as it runs a line across.
This was sliced with Cura - I'm going to try a different slicer and see if I get anything similar. Thanks!