Popup widget does not create a valid date without hour granularity

With the August 1, 2011 dev version:

1. Create a new content type.
2. Create a new date field within that type (date format does not seem to matter) with the popup calendar widget.
3. Select year, month, day as attributes to collect.
4. Create an additional date field with the text field widget (or the select widget).
5. Select year, month, day as attributes to collect.
6. Create a new piece of content. Enter date date into both fields. On attempted save, the pop-up date does not validate with a 'value [date] does not match the expected format' error, but the plain text entry date will validate.
7. Edit the popup-widget field to give it at least hour granularity.
8. Create a new piece of content. Both date fields will validate.

Please let me know if you need any more information.