That sounds like a bug to me. I've never had that happen to me, with or without addons installed.
(I have had something similar: I'm completely unable to edit the audio settings because as soon as I close the menu down the reset to everything at 80, which means I have to use subtitles all the time because so many of the NPCs are so quiet, or seem to randomly alternate between shouting and whispering.)
You will occasionally need to re-accept the licence agreement if you re-install the game or if it's changed significantly (I think update 2 was the last time), because they legally have to let you know it's changed, show you the new version and have you accept it before you can log in.
But you shouldn't lose all your settings unless you switch to a different server (because they're server specific) or reinstall.