Calculated field doesn't calculate on one computer
I am trying to troubleshoot a pdf document that has some calculated fields in it. In particular, there are two fields which are multiplied together and the result appears in a field next to it. I have opened the file on multiple computers running mac os 10.13.6, 10.12.6, 10.6.8, with Reader 9, X, XI, & DC, and the multiplication happens perfectly and updates the calculated field when I tab out of either of the two input fields. On the user's computer (a mac running 10.13.6) when we open the file and change an input field and tab out the result field doesn't change. On her mac she started with DC, and I have installed X & XI. All are broken, while on 4 different computers back in my office it works perfectly in every version of Reader that I can find. (She is a Standard user on her mac, and with both Standard and Administrator users back in my office everything looks fine.)
I have watched the system.log while trying to get the calculated field to update, and no error messages. Can't find any error messages anywhere, it just doesn't calculate the field when running on her computer.
Anyone have any ideas of what is going on?