When putting nether quartz ore in furnace with comparator, the items disappear.

Happens in Creative and Survival-
When you put nether quartz ore in a furnace with a fuel source, the GUI is exited and upon re-entering, there is no fuel/nether quartz ore in the furnace, although it appears on.
EDIT: It appears that when you apply a comparator to the furnace in either game mode the furnace does as described above.