Not sure if this appeared just now or earlier on, but this small clip of air is splitting the first three slots from the rest of the hotbar for some reason. I have reloaded resources and also removed them to test if it was just those, but it still happens no matter what world, realm, or server I load onto. I did think it was just a slight screen error right where that spot was but it still stays intact with the screenshot when it's zoomed in. It isn't noticeable when you highlight a slot next to it but it shows any other time.

Update: Found out a possible reason. It seems as if it only happened when the screen safe area was set to 30.2. When changing it to a slightly higher scale, it removed the small missing clip. Not sure why this happened still or if it was always there, but it should just be an issue that isn't entirely important to fix as it's only minor and doesn't really affect gameplay.