401k catch up set to pretax but appears to be taking taxes for one EE

Hello,

We have one employee that is taking 50% pay to 401K and 50% to 401k Catch up. We were expecting zero net pay and no taxes, but in reviewing her pay stubs,etc. there are taxes taken out. The 401K at 50% is correct, but the catch up is only taking 37.5% and it appears the taxes and remaining net pay represent the other 12.5%,  I have verified the DBA for Catch up is defined as pretax. Many EEs use the DBA for 401k Catch up and it calculates correctly when not trying to use up the entire pay check, so