This is a known problem with tags written by MediaMonkey.
It incorrectly writes two date tags as reported
here and
here.
You can fix this by retagging the files:
- Select all your files and open the Properties dialog.
- Select the date field, and choose Tools, Selection, Format from other fields.
- Set the format to: $meta(date,0)
- Verify that the date tags are properly filled now, and apply your changes.