The bug
If you replace the fuel in a lit furnace with a worse fuel, then the furnace GUI will appear glitched after relogging. This has always been the case (see MC-10025); however, the glitch is far more severe as of 23w31a.
How to reproduce
Put raw beef in the ingredient slot of a furnace
Put a piece of coal in the fuel slot
→ ✔ The coal is consumedPut a stick in the fuel slot
Close and reopen the world
Open the furnace GUI
→ ❌ The furnace GUI appears glitched
Relates to MC-264260.