When adding line breaks in the Notes section of my character sheet (that is specifically, the 'Backstory' and 'Other' tabs; haven't tried the others yet), there seems to be a random chance of additional line breaks being added upon saving the note (for example, a single empty line becoming three empty lines). Leaving the note's edit window and re-opening it allows me to manually remove these additional line breaks, but it's a little tiresome and would probably be annoying during a game, since I plan to use the Notes section to keep track of variable values that my features don't have trackers for (such as the number of uses left for my Steel Defender's Repair ability, or the hit points of the various parts of my Daern's instant fortress). Is this a known issue?

For reference, the browser I'm using is Firefox in case this is relevant. Furthermore, there is also the chance that the opposite effect also happens occasionally (that is, multiple line breaks disappearing when I delete one), but I'm not sure there.

Don’t add a linebreak, just hit [enter/return] (without the [shift] key) and it will automatically add the break for you.

Just hitting [enter/return] causes the same problem.

I will type out normally in the notes second, just using [enter/return] to start a new line and when I save and exit that box, half of the lines have become double spaced. Trying to delete just one extra line break also, as OP speculated, occasionally deletes both lines.

I use both firefox and chrome and the issue occurs on both,