I really like the idea of having a profile system. While I probably wouldn't recommend it for multiple users (I'd actually recommend running multiple profiles on Firefox for that. See: https://mzl.la/3xZQFgI), it does have some good potential for other features that are on my to-do list. I've added it to the list of features I want to add, although it probably won't be added to the add-on for a while.

As for the bug you reported, I've tried to reproduce the issue, but I can't get to happen. If you could either file a bug report on GitHub (https://github.com/WesleyBranton/Custom-Scrollbar/issues/new) or email me at [email protected] with more information, it would be much appreciated.