The controller in the "Arhu's Failed Experiment Quest" seems to still be bugged. Getting in range to use it, I'm getting the NPC chat text that suggests the various commands I issued worked - but when the bot's turn comes up, it clearly didn't.

And I'm not using lightning or anything to recharge the boss in between.

Frustrating given that my party makeup isn't designed around multi-CC, which seems to be the alternate path for beating him.

I experienced the same thing. The controller is extremely useless, probably due to bugs.

One option you have is to let the quest go for now and then come back and beat it after you are a few levels above that robot monster. Your over-leveling will make the battle much easier. That same principle also applies to other monsters too.

Yeah, I considered that but wasn't sure if I'd be cutoff from doing it later or even if it was required, since at least based on the diary it's on the way to the necessary boss. The only other random wilderness mobs I've found are even higher level.

Ultimately I changed the setting to story/easy mode and spammed the switches. Even then it took me several tries given his resistance to freezing and how hard he hits (he 2-shots instead of 1-shots).