I was charging my Quantum Helmet in an MFSU. When the helmet finished charging, I shift-clicked to send it to my inventory, but instead, it disappeared. I think that I shift-left click but I may have shift-right clicked by mistake. In either case, the item should not have disappeared.
The MFSU was directly connected by 2xins gold cable to a reactor chamber which was on at the time.
I searched the area and had no luck finding the item.