The Bug:

Decorations can occasionally replace logs that support mineshafts when generating.

Just for clarification reasons, decoration blocks are blocks such as grass, moss carpet, azalea, dripleaf, cave vines, pointed dripstone etc...

Here is an example:

Seed: -7637587106394010081
Coordinates: /execute in minecraft:overworld run tp @s 71247.81 -22.00 -62.01 -1316.63 7.95

Steps to Reproduce:

1. Generate a world with the seed provided above and teleport to the given coordinates.
2. Look closely at the generation of the mineshaft and how nearby decorations intersect its supporting logs.
3. Take note as to whether or not decorations can occasionally replace logs that support mineshafts when generating.

Observed Behavior:

Decorations replace logs that support mineshafts.

Expected Behavior:

Decorations would not replace logs that support mineshafts.