Platform, device version and operating system:
Mobile, not sure (game version 4.0?), Android
Screenshot or image:
Image showing unbeaten room The Iron Gate:
Image showing Delve map for context:
Image showing (also unbeaten) room Vampire Hive:
Image showing Vampire Hive stats:
(Screenshots of other troops’ stats were also taken)
Image showing defeated room The Iron Gate:
Image showing subsequent Vampire Hive stats:
Battle verifying Vampire Hive stats:
Image showing other traits affecting Vampire Hive stats:
What you were expecting to happen, and what actually happened:
After defeating the delve room The Iron Gate (dwarves, epic) with the Room Effect, “All future Enemies gain 8 Armor”, future enemies gained 8 life instead.
The same kind of mix-up happened on another delve, but the other way around (part of my testing). After defeating the delve room Worm Tunnels (Kruarg, epic) with the Room Effect, “All future Enemies gain 8 Life”, future enemies gained 8 Armor instead.
How often does this happen? When did it begin happening?
This always happens - I believe this is a consistent/persistent issue. I’m not sure when it began happening exactly, but I first started noticing it anecdotally a couple of weeks ago, and checked it properly today.
Steps to make it happen again
Begin a delve containing a room that has a Room Effect that increases Armor or Life.
Before defeating that room, click on one of the other rooms (or all of them) and check the enemies’ stats by scouting them.
Defeat the room.
Check the enemies’ stats again.
If you really want to verify, go into one of these rooms and battle those enemies. The stats are the same in-battle as when scouted (not taking into account traits that trigger at the start of battle).
This may affect Attack and/or Magic as well, but I didn’t check those. It may very well also affect rooms with Effects that give a boost to two different stats at the same time, e.g. Bullette Lair with the Room Effect, "All future enemies gain 4 Life and Armor". Of course, you wouldn’t notice the difference if it was happening in this instance. (In fact, after looking back at some of my screenshots, it may only give a boost to one of the stats, or give both to Armor).
Crazy, right?! I first noticed it when I was fighting the Mimic room in Crypt Keepers, after beating the Kruarg room that gives +8 Life to future enemies - but they all had 7 Life!!! That’s un-possible.
I was paying attention to their Life:Armor ratio because I was using Tesla 
.