When K2+Graphite & Diamonds are combined there is an impact to Slowdown Capsules.

K2 puts them in Weapons 1, unlocked with basic tech cards.
Graphite & Diamonds adds Fullerenes to the recipe, but Fullerenes requires chemical science.

Few simple options I can see:
1) Remove the Fullerenes requirement, returning to 'K2 vanilla'
2) Move the recipe to unlock with Fullerenes, delaying slowdown capsules until chemical science
3) Replace the fullerenes with graphite, keeping the spirit of both mods.

I don't use the slowdown capsules myself but my take is it's best to leave them where K2 put them in the tech tree.

Thanks for the report. I'll try to fix up this inconsistency sometime soon.

Fixed in latest. I decided on option 1. Fullerenes get a few other good uses in K2 so I think it's not a major downside to remove them from slowdown capsules.