Resetting metronome marks in the Properties panel

Why is it, when I sometimes reset metronome mark speeds in the Properties panel, if I type in 44, let’s say, then the “Tempo bpm” display reads 43.999. I understand that this is not at all different from 44, and the displayed metronome mark in the score is still 44, but why does Dorico do this?

In this thread, I explained why the actual tempo displayed in the properties panel is sometimes slightly greater than the desired tempo. In doing research for that thread, I also observed the behavior @SPH is describing in this thread, but I have no explanation for it. Only the developer who implemented the spin box for the tempo in the properties panel is likely to be able to explain this behavior.