When a valid date is entered using a format different from the format specified by the form date field, Acrobat automatically converts this to the specified format on-screen. However the saved data remains in the originally-entered (incorrect) format.

Example: Field Name: "DateOfBirth" Format: mm/dd/yyyy

Entered: "12 Aug 2002" Form displays: "08/12/2002" following entry

It APPEARS the date was converted to the specified format.

Export Data saves this as: ... <</T(DateOfBirth)/V(12 Aug 2002)>> ...

This indicates the original entry was saved, not the converted date.

This SHOULD be saved as: ... <</T(DateOfBirth)/V(03/12/2002)>> ...

When returning to the DateOfBirth field the display reverts back to "12 Aug 2002" (the original entry). It SHOULD continue to display the correct format "08/12/2002" any time after auto-formatting of the date has taken place.

For fields using ISO 8601 (yyyy-mm-dd international standard date format) it is even worse. Auto-conversion to the specified date format completely fails. Only yyyy-mm-dd entry is accepted. Valid dates in other formats cause an error:

 Warning: JavaScript Window -
 Invalid date/time: please ensure that th date/time exist. 
 Field [ DateOfBirth] should match format yyyy-mm-dd

This has never been a problem until recently. Testing other PDF applications shows they are capable of handling the auto-conversion of the date format as expected using the same form. (The form was created entirely in Adobe Acrobat DC.) FOXIT Reader works correctly. Even EDGE browser works correctly. Adobe Reader DC and Adobe Acrobat DC were working correctly UNTIL RECENTLY, but now fail.

Windows 10 Pro with Adobe Acrobat DC (20.012.2004)