Unfortunately, with the last release of the Calendar Field a bug has slipped in.
Once you edit an entry with a calendar field, the field's data are saved incorrectly and as a result further changes of the field's data are not longer possible.
Please update the Calendar Field to version 2.3 as soon as possible.
After that you need to perform a database query as described in the bug report.
We are sorry for the inconveniences.
The Calendar field is available for Silver and Gold Subscriptions.