Hi

I'm a new/old user of Piwigo.. I've had Piwigo installed on my server before and then deleted it. I've recently installed 2.9.2 and installed some plugins..

All was working well, then suddenly I started getting these errors when I go to my galleries.
This only happens when I click on any picture within my albums.

Notice: Undefined index: day in ...../public_html/piwigo/include/functions.inc.php on line 665

Notice: Undefined index: month in ...../public_html/piwigo/include/functions.inc.php on line 671

Notice: Undefined index: day in ...../public_html/piwigo/include/functions.inc.php on line 665

Notice: Undefined index: month in ...../public_html/piwigo/include/functions.inc.php on line 671

I also see a similar error in the configuration page/Options General tab where there is the "week starts on"

Notice: Undefined index: day in ...../public_html/piwigo/admin/configuration.php on line 366

Notice: Undefined index: day in ...../public_html/piwigo/admin/configuration.php on line 367

I've tried checking the mysql (mariadb) tables and those that reference day, month, year is the history.summary and they are blank.

I'm think if dropping the piwigo database and rebuilding the installation again, but I want to understand what happened and try to fix or avoid it next time.

Piwigo version: 2.9.2
PHP version: 7.1
MySQL version: MariaDB 10.2