Hey Scott,
I agree that is very odd, especially since it is only happening to your one User, I'm pretty stumped myself at what that could be exactly.
What we can try is, I can create a copy of the screen and see if I can find anything that looks off. If I do find any issues I can follow up with that information and you can make the adjustments on your live screen.
If you would like to try this route email me over your company account, exact screen name and turn on MethodSupport (which will allow me to login into your Account). Also in that email note down the User that is running into this error, that may help.
My email address is in my signature.
-- Mortaza