Problem
Forms may merge leaving field codes rather than the expected data when the field code and the field result saved in the document do not match.
These will look like «68» (with various other numbers) in most cases.
Solution
Remove and re-insert the errant fields using Forms Workbench via Main Menu > System Maintenance > Forms Workbench.
Note: Don’t make any changes here if you are not familiar with the process or setup of these forms.
Updated