I am having the same issue with one paycheck for one employee that I am trying to create for the first quarter of this year. Every time I create the paycheck it increases Employee Social Security and Medicare Withholding  by even more than the previous attempt. I have verified data and performed a rebuild and rebooted as well as updated payroll and QuickBooks several times. My accountant and I have been working on this all day. There is obviously a glitch with Quickbooks and I have no confidence that anyone I reach in Support will help based on past experience.