Barline keeps appearing at end of blank measure at end of line

[dflat]

...Also what about the one barline that I could delete, then create the beginning one on the next line without it reappearing - but it would reappear the next time I edited it? Seems like a bug.
...

The idea behind a single left barline at the beginning of a system (new line) creating a right barline at the end of the system above (at the right end) is this:
When you are adding [chords ... Next, next] ... left barline, [chords ... Next, next] ....left barline, you can do this quickly without having to think about the location of the cursor (moving to the next measure or system). No need to add the single right barline at the end of any system because it is created automatically.
If you are starting a new line with a left double barline, then normally you would have ended the previous measure (system above, at the right end) with a right double barline or closing repeat barline.