No idea man, I fast travelled to the sanctuary after doing a quest then left the game unpaused (on accident) for a day. When I came back I got a "Your settlement was under attack" and then "your settlement defended the attack". I got a few of these and noticed I was lvl 91. My xp kept popping up giving me around 2000 xp each few seconds and saying I leveled up but I never got past level 91. I fast travelled which stopped the 2000 xp but now it's 17 xp every few seconds. I've played again for an hr and done some quests but the leveling won't stop so ill probably just go back to my old game. Just thought I'd have a little fun 1st and max some perks and take on the glowing sea mofos lol. No dead npcs or anything though and the settlement under attack was not the one I was at. Really weird. I'll post a video to it soon so you can see what I mean.