Most feasts do not have their hitboxes updated throught the eating process, only vanilla cakes.

This is intentional, due to limitations with hitbox facing.

The hitbox of a block cannot be rotated. For the feasts and pies to have a matching hitbox, we would need one for each of the 16 state combinations, with some being compost hitboxes, which would mean a lot of data for a block like such. On the plus side, a larger hitbox makes it easier to interact with the block.

Not much I can do, sorry. :(