Yoinked from https://ministry.kronosaur.com/record.hexm?id=97836
Seen on the Bogatyr reactors in Elemental Shift, which have a fixed and finite supply of fuel with no refueling items: the game tries to pull the level of the fuel, doesn't find anything, and somehow creates a junk value to fill the space(interestingly the values I saw when I tested it are completely different to the ones seen on stream, so something funky is going on there).
This is in fact a thing that happens on any reactor that does not specify a level-range: you can see it on the Koshiba 200 as well. So it's not the lack of fuel, it's the lack of a specified level range for fuels on the reactor. The game should simply not show levels, instead it generates a junk number from somewhere.