Not sure what is happening exactly.

I made a custom-made datapack that syncs up 2 player's health bar by rapidly altering the max health of the players.
When holding a food that has a preview of potential hearts healed while taking damage, the client crashes.

datapack : soulbound.zip

Forgot about the crash report:
crash-2024-06-25_12.20.35-client.txt

Fixed in v3.0.5, thanks for the report!