Singleplayer Co:Op Bug: Items Vanishing from Hotbar (PC)

So, I have this issue where items are just mysteriously vanishing from my hotbar. All 1-8, randomly. Sometimes it’s when I unsheath the tool/weapon, others it just seems to have vanished at some point of me running around. I’ve watched them straight up disappear. They’re not ‘invisible bugged’ because I’ve dropped everything on me and tested to see if my weight was zero with nothing on me, and it was. They’re just completely vanishing, making it virtually impossible to play at this point. Also when sprinting sometimes it pulls out random things on my hotbar even though I’m not pressing it. Never had this issue before. Some help would be greatly appreciated!