The same custom form should not be published to multiple form libraries. Doing so can cause <forms cache> corruption. There is no way to guarantee that the forms published using the same form name are actually identical forms which can lead to unpredicable results. Some examples that have been submitted for review when trying to isolate unexplained problems with ContactGenie programs resulted in finding that the same form name was used for completely different custom forms which had absolutely no resemblance to one another – either in presentation or user-defined fields included associated with the form.
Custom forms assigned to pre-existing contacts using any available third party tools (such as the messageclass functions found in ContactGenie Toolkit) should always be assigned from the same library that is used when the custom form is assigned as the default for the folder(s) in which it is used. For example, this can occur when the same form name has been published to multiple libraries (Folder, Personal Forms, and/or Exch Org Forms) and the default used for the folder when new items are created is set to one library (i.e. Personal Forms) but when pre-existing contacts are changed to utilize this form (the item’s MessageClass is changed), a different source for the same form name is selected.
Something that should never be done when a custom form is being used is to add/remove fields from the “User-defined fields in Folder” list. Any changes to user-defined fields should be done by changing the custom form design itself and then re-publishing the form to its original library. Any changes made to the form will be automatically applied to any items that have been assigned to use this form provided the same forms library was used when the form was re-published.