I'm currently playing ATM10 version 0.14. There I have a centrifuge (the plain type, not heated or powered, no upgrades) with a stack of gold combs in the input slot to to process. For every tick filling the white/grey arrow by one pixel on the left between input and 3x3 output slots, the honey level indicator on the right flickers between three states, as seen here:

Note that these pictures were taken in rapid succession without changing anything in the centrifuge itself. I'm not sure if it is merely a graphical issue or also would have an impact on the actual amount of honey one could obtain.

do you have other centrifuges next to it?

Yes, indeed, in fact there are 4 centrifuges in a 2x2 area. Breaking one of them led to a state where the remaining three are all full and void of the honey as expected. A single centrifuge seems to be ok as well. I take it they are somehow pushing the honey in some sort of circle?

yup, that's exactly what they're doing

Ok, thanks for the quick response, I guess we can close this then as "works as designed".