Factorio: 0.18.16
Krastorio 2: 0.9.6

As title. A single DT-Fuel Cell is not actually enough to power a full process of the Fusion Reactor. Burning a single fuel cell in the reactor will fill the progress bar all the way, but not actually finish the "craft", so it gets stuck in a limbo with the fuel consumed, but no empty cell returned or steam generated. A second fuel cell with finish the first process, but now that second one is stuck in limbo.

https://i.imgur.com/43OHKo4.png

I mentioned this and why in another thread, but I think there's a typo in the fuel value of the DT fuel cell. it's listed at 10GJ but that should've probably been 100GJ instead.

That wouldn't match the behavior here, though. That would imply that either 1 fuel cell should be enough for 10 cycles, or it that it should take 10 cells for a single cycle. Instead, it seems like the fuel cell is enough to power 99.9999999999999% of the cycle.

I feel like I've seen a similar thing with science packs in vanilla - if you're just using 1 lab, you can eventually watch the "end point" of each cycle creep backwards as each science pack is just slightly less than a full cycle.