Well, compare Librewolf to Brave is kind of pointless, Librewolf is not even a Chromium browser, you have to compare it to Edge.
Or go to “%localappdata%\BraveSoftware\Brave-Browser\User Data\Default\Local Extension Settings” directly and check to see what could be wrong about it, monitor it and see what could be the issue.
As that folder implies, it is the one in charge of Extension settings.
And just to make it more evident how that’s true, you can for example install extension, change their settings settings around, then close Brave, delete every other folder, open Brave which will open as a new Profile, then reinstall those extensions and the settings will be the same.
In my case, I just deleted every folder and file in User Data but
\Default\Local Extension Settings then I opened Brave, installed Tampermonkey and all the scripts I installed were there, not enabled because of some security thing, but you only enabled them and clicked on ‘reinstall’ and done.
Or better yet, a way to do it without userscripts getting disabled and "it just working’ by having the extensions in the same state as before:
Remove everything but
Secured Preferences and
Local Extension Settings, then rename LES to something else, when you open Brave, the extensions show as installed but with an error since they don’t exist in disk anymore, so you have to go to Brave://Extensions and click
repair, then you close Brave, and replace the new
Local Extension Settings with the old one, and when you open Brave, Tampermonkey will have all the scripts installed and enabled correctly, just as they were before.
So that shows that the “LES” folder will control everything about settings, and the secured preferences will just make sure things are secured and not enabled if they don’t match information. There is a Protection → Extensions inside of it with some decoded or encrypted key to do that, but as you can see, not all settings get disabled and they still stay the same even if some information changes about the user.
So you should monitor Local Extension Settings and see what is going on. as far as I know, nothing inside the Browser should remove that, and nothing should touch that unless you ‘factory reset’ extensions or or remove the extension or the extension has to be repaired.
So it is weird it is happening to you.
Maybe some third party program is causing it? because the only time this might happen is if Disk was failing or the computer shutdown and then it broke something about the User Data or if a third party program was messing with it.