Some inventory icons are invisible

When playing on my friends realm, after updating the game to 26.50 i opened the inventory and realized all the item icons from the add-ons that were activated, were invisible. Snow and cobwebs included. I just blamed it on those add-ons and kept playing, until i saw the youtuber EvidentP have the same issue without any mods. Also for some reason my skin doesnt appear in my inventory. How could this be reproduced? Dont got a clue