The bug

The block model file chorus_plant.json is used for defining the item form of chorus plants (MC-120420 incorrectly asserted that it was unused, which it is not). However, this model file completely redefines the chorus plant model shape, which makes it among the largest model files in the game (even more so due to MC-262641). There is no point in doing this, since it can simply reference the chorus flower template model with the chorus plant template file for a visually identical result.

A fixed version of this model is attached which does this - chorus_plant.json can be easily replaced with this attached model to resolve this issue. Mojang have my full permission to use it, if that's required.