EDIT: See below posts for updates
Playtime is 2 days 17 hours
Version is 0.14.2.2
There is nothing out of the ordinary in the debug log
No mods have been enabled, game files are all standard.
This ship has 3 He-3 tanks, 1 D2O tank, and a cryo tank. The reactor contains a laser cap, 2 lasers, fuel supply, 2 fuel inserters, cryo pump, MHD generator.
The reactant remain section of the torch drive reads 19.67 hours. At the drift section of a course plotted to take 19.53 hours of reactant only half of one of the He-3 tanks is consumed. Attempting to plot courses with higher reactant consumption will result in the autopilot disengaging at some point during time skip.
The readouts for fuel consumption/day on the reactor console appear to be accurate.
My assumption would be that this is a bug in the math for the reactant remain value in the nav console, probably dividing or multiplying by an incorrect value.
This bug is easily reproducible with my save files, ping me if I should upload them.