The two 'Fungus' can be bone mealed in both crimson and warped nylium.
How To Reproduce:-
Step 1:- Have a nylium block (Crimson & Warped).
Step 2:- Have a fungus. (Crimson Fungus & Warped Fungus).
Step 3:- Place the fungus in the non representative block.(Podzol, farmland, grass block, coarse dirt, dirt, soul soil)
Step 4:- Bone Meal the fungus.
The Fungus grows in the non representative block.
It cannot be grown.
Hoping this information is helpful to fix the bug.