Found using FTB Infinity Evolved expert mode.
I was setting up my storage drawer bank and the game registered a double click in the upper left compartment of a 4-drawer unit. My ardite was deposited and then the drawer accepted an unknown quantity of aluminum ingots (TiC), destroying them. It did not turn them into ardite ingots.
I also went to retrieve copper (TE ingots) from the upper-left compartment (again) of a different 4-drawer. This time it ate my TiC hatchet.
Summary:
Happened twice. Affects input and output. Always on the upper-left compartment of a 4-drawer oak (so far). Both times involved losing TiC items.
I have not seen how to reproduce this yet.

Just an update. At some point the hatchet reappeared. I know it disappeared because I saw it vanish and my inventory was empty. The aluminum never came back. This may be a rare case or something. I haven't had any other issues. Just be aware of the possibility.