Kansas City earnings tax

When reviewing my Missouri return it tells me to check this entry:

Form MO-A:TP-Kansas /St Louis Refund should not exceed the prior year state and local tax refund reported as taxable on your Federal return. 

 

Because of covid-19 we worked from home most of 2020.  I'm not sure what my mistake is.  It's saying it's not ok for mine but it is for my wife's.