Hello! On activating the child theme from the distribution (no changes) i had the following php warning on pages with portfolio: Undefined variable: type in C:\xampp\htdocs\XXX\wp-content\themes\striking\framework\shortcodes\portfolios.php on line 345
The problem fixed itself.... I had used some existing posts which i converted to "portfolio" post type. This way, come custom fields weren't set. After updating the posts the php warning vanishing. But thank you for your answer!