Finally decided to lock in and finish a run, took a few attempts to get going.

So, I'm doing a vanilla classic ironman playthrough, and ai'm doing the base defense. First time doing it so not really sure what to expect. I get to the second wave (the flying enemies one) and I see two cyberdiscs and two drones roll in. I think "shit, cyberdiscs are scary. I'll stay back on overwatch though I think it'll be fine." Kill the remaining berserker and stand back, and then from the direction they were in, a cyberdisc rolls out and kills my corporal heavy who was apparently not in cover anymore (he was before.) Second cyberdisc comes in, shoots my mec for 9. Then,

a third and fourth cyberdisc show up and kill my mec outright.

I'm willing to believe this was intentional (they really love cyberdiscs even though they are way fucking worse than every other enemy of their class) but it sure did feel like a bug, in that exactly twice as many discs as it showed me appeared.