The excellent mod Enhanced Invisibility by powerofthree fixes some bugs related to the invisibility mechanic in the game. However, it also changes the Invisibility and Ethereal Form behavior so that activating objects does not break the said forms respectively. Although some may prefer this behavior, it makes the game too easy and takes away the challenge of sneaking into homes. With that you can cheese your way through quests like Missing in Action, which isn't immersive. But not anymore!
This tweak simply changes that behaviour back to vanilla, where activating any object will break the Invisibility or Ethereal Form.