I had this exact issue as well. After hours of fighting with text boxes and such the following solution worked for me.
Add a wrapper function.
i.e. Create a new function that only has the formula that would have gone in the footer.
in my case it was
Diagnosis - disp
{@Diagnosis (footer)}
In your case, it would have been
Display
{@Display}
Or something like that.
This allowed crystal to correctly export the entire formula instead of incorrectly overwriting several of them.
Thanks