Steam wouldn't let me post in comments, cause of an issue on my end.

May not actually be a bug. I will delete the thread if that's the case.

If I choose for example 2x multiplier and tick the affect Passive skills in "Character" sandbox settings, then the UI Skills panel and character creation screen won't report Strength and Fitness having a 2x multiplier, but will for all the other skills. It has to be an issue with how this is handled by the mod as setting a custom 2x xp multiplier using this mod's sandbox settings, reflects the change correctly in the UI. All XP boosting features work as expected and it's only a visual but confusing to the end user bug