After Curie's transformation into a Synth, I assumed I'd be able to revive her with stimpaks, given that Gen3 Synths are mostly organic now.

But when I tried it, there is no option to Stimpak her.

Is this a holdover from the code that designates her as a Miss Handy unit?

Codsworth has this issue too, I can't revive him in battle, I have to defeat all the enemies and wait for him to reinitialize.

I haven't played with Valentine or met X6-88 yet, so I don't know how they compare as regards to Stimpaking.