I am using advance options app and have also posted an support issue with them, but I don't think the app is the issue.
Here is a link to a product. This happens on all products that allow more than 1 quantity. There is plenty of stock.
If I add more than one item using the quantity +/- , I can not check out.
I get an error that says: Requested Quantity is not Available.
I have checked every setting and Googled to no avail. I can not find the issue.
I also noticed that the quantity selected on the product does not port over to the cart. If I select a qty of 5 it only puts 1 in the cart.