Mushroom breaks on tuff block when generating

I dont know if this is a feature or a bug, but it might be a bug so il send anyways. Red mushrooms/ brown mushroom generating in drops into items when growing on tuff block. Its not much but it really weird for that to happen.

seed:-894938320998262692

coords 206 -9 -253

seed:7753075226904391792 (this msuhroom grow on the tuffblock above and breaks)

coords 241 80 79