I had an order this afternoon and 3 of 10 items showed a negative quantity remaining.
All of the three shared this general pattern:
We had X parts for sale.
Buyer purchased X parts.
Stock remaining was listed as -2X. (And put in stockroom).
I then checked another lot.
We previously had 82 parts for sale.
Buyer purchased 22 parts.
Lot showed 16 parts remaining.
It subtracted the triple the number of parts actually sold on all of these lots.
There are 6 more lots in the order that I have yet to check, but some of them
have remaining quantities in the thousands, so I am loathe to count them all
up.