It turns out they did indeed. Solved with a bedrock pipe and a few more refrigeration units.
Now the plasma setup seems to work fine aside from a terrible lag, but unfortunately it only leads to the next problem, this time it's really wtf: neutron absorbers dont seem to share their heat with boilers. There's literally an absorber at ~250+ degrees with a couple of boilers next to it at ~6 or even -2, that's minus two. I assume they do disperse some heat somehow since they dont overheat. But the steam is not being produced, obviously. It wasnt always like this, the first few test runs did produce steam before plasma leaked all over the place and/or absorbers melted down due to not enough boilers presumably. I remember seeing boilers at 400+ degrees back then.
I'd check the issues github; I haven't looked into it much, so I don't know exactly what the deal is, but I know I've seen several posts about similar problems.