AcroForms VBA plugin does not correctly populate checkboxes when form contains XFA
Or rather, it populates the checkboxes correctly as far as the PDF side goes: it sets the /V and /AS of the checkbox objects in /Fields correctly, but it doesn't set the XFA side accordingly, whereas it does for text fields. In the Acrobat window the checkboxes show as correctly marked until I close the file. When I reopen the file with Acrobat or Reader, it gets its display information from the XFA, not from the /Fields (and that may be the real bug here), and so doesn't show the checkboxes as marked.
Jerome Colburn commented
In addition, Acrobat and Reader's behavior in setting one of a group of checkboxes (such as the Filing Status boxes on the 1040 form) is not correct either. It should set the /V of only the selected box to its export value and should remove the /V field of the others.