Unlikely to be a bug.  Is your client's VAGI below the threshold for filing?

• Single: $11,950
• Married filing with spouse on the same return: $23,900
• Married filing separately (on separate forms): $11,950

Thanks for the reply. I think what's happening is that this is a dual return with both Virginia and Maryland and due to reciprocity rules, the MD return is taking all the tax and VA is zero.  They lived in VA for 2 months then MD for 10 months.