Armor stands can no longer be placed on top of fences, walls, or fence gates

The Bug:

Armor stands can no longer be placed on top of fences, walls, or fence gates.

This issue didn't exist in 1.16.1; it first appeared in 20w27a.

Steps to Reproduce:

1. Place down a fence, wall, or fence gate.
2. Obtain an armor stand and attempt to place it on top of any of these blocks.
3. Take note as to whether or not armor stands can no longer be placed on top of fences, walls, or fence gates.

Observed Behavior:

Armor stands can no longer.

Expected Behavior:

Armor stands would be able to be placed.