OK, today was the next episode in the ongoing saga of fredrik & the opamps: turns out that if you need your opamp to work as a non-inverting amplifier, you shouldn’t connect the feedback to the positive input, because that turns it into something else 
(luckily I have plenty of PCBs where I didn’t mess up the opamps, otherwise you’d think someone was trying to tell me something 
)
(also, it was an old PCB that I just hadn’t gotten around to test. I think I’ve gotten more careful…)