A patch to “dooring”, possibly.

Today there's a 100 Ride the Lightning 4P with the modifiers Fire Storm, Epic Mini-Boss, Slowing Pools, Wall Weakening, and Slowing Attacks. In this mission I had set up a metal fort with a Heavy B.A.S.E Kyle loadout, and I was lazily using doors to speed up my solo. Things got really interesting.

On the first defense stage, I was just farming close laying cars when I noticed that Zeus had taken a bit of damage. Running over to access what had happened, there wasn't even a scratch on the fort. I stayed and watched as a bit more damage was inflicted, seemingly for no reason.

So now I'm watching really closely as I begin the final stage, and again, Zeus starts taking more and more damage, finally getting to a critically low state which I just let happen as I watched, perplexed. The van was destroyed and I lost.

Now there's no modifier active that would permeate damage inside the superstructure like death bombs or acid pools, and there was no Sploders or Lobbers. Curious. So I loaded it up again and tested it.

On this test mission I found that the same thing happened in the first stage, the van started taking a bit of damage for no apparent reason. However, the instant I edited the doors away, the mysterious damage stopped. On the final defense stage they sent the kitchen sink, Sploders, Flingers, everything, but Zeus didn't take another pixel of damage.

So… it would seem that perhaps they're still allowing for doors to do their Chester Cheetah thing, but damage can now somehow seep through to some extent, in RTL missions at least.

I dunno, test it out, see if you can figure out what's happening.