AccountRight Negative Inventory Value

Good morning,

I noticed that one of our products had a negative inventory quantity on hand.

When looking into the item history I found it had been sold/invoiced without the stock showing as being on hand.

We build this product from several items, so this was a concern as the other products did not have their stock adjusted when this item was sold/invoiced.   

I have had to adjust these products manually, please explain how this can happen.

We also have several items with odd formulas in the "On Hand" and when you go into the item it has a nil value on hand.

Thanks

Cathie