This is likely an effect of how we currently paint the dotted line. We currently paint a gray dot at the first y pixel of the line, then every other y pixel after that. This means that, if the height of a line is an odd number of pixels, then its "last" pixel will be directly adjacent to the "first" pixel on the next line. A fix should be simple: always paint dots for the indent lines on y-pixels with even (or odd) values.
I'll make this change soon. Thanks for pointing it out!