I used my healing kit on itself to determine the number of charges left on it while I had Naryldor De'alow's store open in the merchant hall. Judging from the dialogue box, it attempted to combine with itself, doubling the number of charges and the item was then deleted.
(http://imageshack.com/a/img585/4277/ewjg.jpg)
Fixed. I don't think there was a previous use of targeting the healing kit to determine uses left. Shouldn't be a problem anymore.