2x2 Spruce and Jungle saplings will not grow below Y=0 [C&C Experimental]

Spruce and Jungle saplings placed in a 2x2 configuration will not grow below Y=0; individual Spruce and Jungle saplings grow properly. Dark Oak is unaffected and grows properly.

 

Steps to reproduce:

1. Create a new world (tested in 1.17.11 and 1.17.30) with Caves and Cliffs experiments enabled.
2. Create a air column that extends into negative Y levels. Be sure to include walls to insure water or lava that may be w/i the fill area can't flow in.
3. Place dirt such that saplings will be planted a Y >= 0
4. Demonstrate proper growth in 2x2 configuration using bonemeal
5. Clear obstructions from #3. Place dirt such that saplings will be planted at Y<0 (I used fill for Spruce to insure Y level placement and place Jungle by hand).
6. Demonstrate growth failure using bonemeal
7. Plant individual Spruce and Jungle saplings and use bonemeal to demonstrate proper growth of 1x1 planting at Y<0 
8. Clear growth and demonstrate Dark Oak grows correctly a Y<0

 

Video demonstration: https://youtu.be/Fg9NyZh0aHw