So during A Brewing Storm my horse spawned inside the fighting circle. Perhaps it was "parked" at that spot when I entered the longhouse before the nap on the bed. Unfortunately I haven't taken a picture of this but it was really there. It got in the way during the fight so unfortunately it got killed and now the corpse is forever stuck outside the longhouse. It did change skin after I changed my mount btw.
Also since this fight the tattoo lady, Tove, is not inside her shop anymore. She stands between the straw puppets at the assassin's bureau. Please see below
Given the fact that this mission causes other glitches/bugs as well I do believe it caused mine as well. Would really love to get my settlement normal again. Adding a new building didn't solve it. I can still upgrade from level 5 to 6 so maybe that'll solve it but if an update could fix it I'll take that as well of course ^^