Are your tables "Linked" tables? ... if so, then refresh your links first and see if that does the trick.... if not ...
Clear the recordsource of the Form ... move the focus of the cursor to another property, then go back to the RecordSource property and type out your recordsource again ... this will "Refresh" all the hidden properties and such the Access maintains for a bound form.
Many times there is no need to do this, but, as I recall, it seems to be more frequently needed for linked tables.... I typically do it as "good measure" before I even look for my newly created fields in the field list.