Is this wrong? I have seen it more than once now so I have to ask.
it is not the fitting that is supposed to go there but much more better than duct tape…
Hard to call it wrong. In my opinion it’s ok if the fitting is certified for plumbing application. Most importantly if no leaks and doesn’t interfere with proper draining…it passes!
This is common to find in Rental units. The reason is the thread design to tighten on the stub out can be moved easily and then the apartment will flood. Smart Owners will install this to prevent that from happening. It takes much more effort to yank those off the pipe when they are tightened down correctly. Only thing to watch out is if there is applied pressure to install it where it is. Your picture does not show this.
One other thing is if you are in doubt. Try turning the clamp with just light pressure.
It is done all the time with that rubber coupling. It is usually used to tie the plastic trap arm to a copper drain pipe. I see no problem with it.
I assume everyone else is assuming the stub out is metallic? It it was galvanized steel, it may have threads. If it was cast iron it wouldn’t. These no-hubs or ferncos were never designed to go over threads. Besides, why wouldn’t you call it out for no marvel connection?