I think the author knew he was going to be axed or got axed for this chapter, drug use is a taboo in Japan, and usually they make a thing only villain or secondary, weak characters are handling.
This stuff was weak and seems like it made them drunk, but still, the author gave the main cast mushrooms.
Being shut down for doing something like this is absolutely possible, and most mangaka know it, any editor would stop them too, so I think the author just said "screw it, they axed it anyway".