I added a "portfolio details 2"-block to my site and once I'm going to click "Add new info" I am getting this error:
"Undefined offset: 0" on line 398 of /var/www/example.org/example/public/modules/backend/formwidgets/Repeater.php
which is pointing to
$this->childIndexCalled = (int) $matches;
I managed to fix this error with latest update. Please update your theme.
Let me know if that helps you