We've had similar problems with the QC module in Classic, but have not yet tried EVO because of our bad experiences.
The problem we had in DBA Classic, was that once we received something into QC, and then released it as OK, all reports and screens would show the item in inventory EXCEPT when trying to post an invoice for that item. In the accounting screens and ONLY in the accounting screens was the item still unreleased from QC.
We have not yet had the courage or the time to test this function in EVO