Treasure Room found as a normal room

Platform, device version and operating system: PC/Mobile (Steam)

Screenshot or image:

What you were expecting to happen, and what actually happened:
While running through the Underspire, I found a treasure room that was marked as a normal room. I did not get a treasure reward from it. I was not expecting it. I’m not sure if it’s a bug. Is the treasure room (or other trap rooms, for that matter) available in the pool of random rooms to encounter outside of the special rooms?

How often does this happen? When did it begin happening?
First time I’ve seen this happen.

Steps to make it happen again
As far as I can tell, it’s random.

I encountered one of these myself earlier in the week, but didn’t realize it until the next room was a (legit) Treasure Room.

This is basically the same as when the Gnome room (from Deep Delves) would sometimes appear in Underspire the same way – albeit without the actual Gnome.