Mushroom spawned on wood plank

I found a mushroom in a village house that was on wood planks. It made no sense on how it was spawned there and how it's not being destroyed instantly due to the fact it cannot be placed on that block.

seed: -2379844725122361130
x:59
y:65
z:205
This is where the mushroom is near you have to spin to find it depending on how you are faceing.