Summary:
In Java, bone mealing warped nylium can sometimes generate crimson roots and twisting vines. In Bedrock, this does not happen. Only warped fungus, warped roots, nether sprouts, and crimson fungus can generate.

Steps to Reproduce:

1. Create a large platform out of warped nylium
2. Bone meal the warped nylium many times

Observed Results:
Crimson roots and twisting vines never generate.

Expected Results:
Crimson roots and twisting vines should have a chance of generating, just like in Java.

Videos:
Java:
Minecraft 20w45a - Singleplayer 2020-11-05 15-35-21.mp4