I am having the same issue with just normal invoicing. The issue is very challenging as it doesnt happen all the time. I've neem using quickbooks online since July of this year. the issue started around mid to end of august.
It seems to pick certain part numbers to have the issue. I've tried invoicing a different customer the same number and the quantity will dissapear.
The technical people at Quickbooks are not helpful at all. I've submitted two technical calls and they have assured they are making it a priority. Nothing back from them at all.
I'm searching all over the web for a solution to the problem Personally I think they have a known programming issue that they cant fix.
Coleman
