Hi miguel1258 ,
Apologies for the late response. We have had a long holiday weekend the last week.
Yes, we give support here.
We tried to reproduce your issue in a local installation. It worked as expected.
Please answer the next questions:
Does the problem repeat when you create a new PO with the same product? What's the difference between this product and the products with quantities added correctly? Does the error happen with any other product?
Best Regards,
José Andrés