Discovered this bug when trying to freeze to death in powdered snow. Afterwards I tried hurting myself on pointed dripstone (stalagmite ver) while wearing no armour, and my hunger stayed saturated at full, even when my health was almost gone. Even after jumping in lava and quickly getting out my hunger bar was full.

I attempted to do this for several minutes to try and lower my saturation.

update: after reloading the game it seems like the hunger is going down as normal, however it still feels slower than normal