Like the title says, while frozen from being in powder snow the heart icons being rendered while holding food are normal hearts.

To reproduce: place down powder snow using a bucket, walk into it and hold a food item. This results in:

The rendering should probably be disabled the same way it is when affected by poison or wither effects. For this there is a isFullyFrozen() method inside the Player class.

I am unsure how early Mojang implemented those custom heart icons while freezing, but I have tested this with 1.20.2 and above.