Bug:

When growing both types of Fungus (Crimson and Warped) with bonemeal, any slabs that is above it will be replaced by the tree. Any blocks above the slabs will remain there.

How to Reproduce:

1. Place fungus in an appropriate spot for growth
2. Place slabs above it (enough for tree growth)
3. Use bonemeal on fungus until grown
4. The tree has now replaced the slabs but not effecting any blocks above it