Just an FYI, I recently upgraded my server to Fedora 27, along with all the trappings (including PHP 7, newish MariaDb), and this necessitated upgrading mate as well. I discovered that the current version of mate tries to set default date to a blank string (''), and MariaDb now is set up in strict mode, which is not happy with this. I had to modify formatDate() line #1494 of AjaxTableEditor to return '0000-00-00' instead of ''.
Hopefully this can be of some help!