I get those confusing -xxxx XP from time to time......as far as i can tell, only once did it ACTUALLY remove some of my xp tho. Never knew why. 1-crafting the door charge in the tutorial -32k to -330k xp
2- Looted a crate in junkyard -12k XP (This one actually WAS deducted from my XP total.)
3-Crafting a prototype from Encrypted Holodisk.
Now im curious what happens if im lvl 24....then lose enough XP....do i drop to lv 23? If so...do i lose my perks? If i DO drop to 23 and DONT lose my perks and skill pts can i glitch the game to get infinite lvl 24 perks?........