Not sure where to put this

Okay, so I was trying to do a T2 run just now... I was hoping to be able to do the Roarmulus twins so I could get enough tokens for them science guns (what else can you call them?) since I was just one token short of the price.
Anyway, BEFORE I could get into the Ironclaw Munitions factory, I had to do an Arena.
Keep this in mind... I had come down expecting Constructs and a few Gremlins, the only other enemies I was really expecting were the Quicksilvers. 2/3 of those dudes do Elemental damage. I had thus equipped myself with whatever I had in this regard- Owlite Shield, Bomber Set, Nightblade, Shockburst Brandish (You can pick me apart on my choice of equipment later... let me get to the point... and the Nightblade is because I wanted to waste Menders and Quicksilvers FAST). No, I do not have any other weapon slots. I don't HAVE that kind of CE.
The Arena was Venom Fang: Robo Rampage.
ALPHA WOLVERS AND POLYPS
THOSE AREN'T ROBOTS
Well... Not much problem with the Polyps since I had them covered, but the Alpha Wolvers, with their 3x unstoppable lunge-and-bite PIERCE DAMAGE combo... 6____9
I don't know whether or not this is intentional or a glitch.
It must be those since the only other explanations are
1. Wolvers are cyborgs in spite of the game calling them Beasts
2. OOO failed Kindergarten (or they still are in Kindergarten. Those science guns sound like something a 5-year old boy might have come up with sans "destroys all girls and homework")
3. OOO doesn't give a flying road apple about this (and this is CLEARLY not true)
ITT: Post if your Clockworks Runs have ever been messed up by an enemy you kinda weren't expecting.

I met Wolvers and Chromalisks in Mechanized Miles and Greavers with Devilites in Haunted Passages.

I was covered for the Menders since I could predict I'd be seeing a lot of them- The Nightblade I was carrying. Had I seen a Silkwing you'd see a lot more profanities/euphemisms-for-profanities-since-GMs-like-to-rub-soap-in-my-mouth in my post since they also have the SIZE ADVANTAGE and can end up stuck in the middle of a crowd of Lumbers, Retrodes and Menders where they HEAL ALL THE THINGS seemingly non-stop and you can't even TOUCH them
At the present time I am both phobic of Royal Jelly Palace and incapable of getting through the pre-boss levels even with help.

lumbers/mechaknights/wolvers are like universal to all arenas no matter what type the level is. The same goes for the Colony/trojan of the first room.
I would say this happens because the level would beceome rather simple and dull if you only had to fight strictly the same family plus the differences in enemy damage means no armor would be perfect for the level, leaving room for variety.

In any given arena, the last mob I see is still a swarm of mecha knights about 75% of the time. The rest of the time it's wolvers or gremins. I have yet to see any other swarms in the last wave.
As for other floors, I generally see about 50% of the total monsters matching the theme. This means, if I visit a construct floor, I get about:
50% construct
10% gremlin
10% slime
10% fiend
10% undead
10% beast
Give or take. It seems like gremlins hang around constructs, and the same goes with beast/slime and fiend/undead. Monsters tgat deal the same damage type just seem to naturally occur in similar areas.

1. Wolvers are cyborgs in spite of the game calling them Beasts
2. OOO failed Kindergarten (or they still are in Kindergarten. Those science guns sound like something a 5-year old boy might have come up with sans "destroys all girls and homework")
3. OOO doesn't give a flying road apple about this (and this is CLEARLY not true)
You missed the fourth and fifth possibilities:
4) OOO wants to mix it up to keep those with pure elemental resist gear on their toes.
5) It's a bug.
I'm going with number 4.
Monsters are mixed in any level, apparently by design. Were there any healers in that arena? A mender (gremlin) or silkwing (fiend)? I bet there were. So why aren't you complaining about them? You're complaining about the wolvers because they're difficult. The solution is to carry a piercing weapon (or to get more skill).
Also, a weapon slot upgrade might not be as costly as you think. If you farm the Royal Jelly Palace (especially using well-placed friends), then you can earn 250 CE in two days. And often you can buy the upgrades for less than 250 CE, from people who've spent money. Consider it. :)