PHP Error Message deprecated function

Hello,

today i realised that i got an issue loading descriptions from custom post types that belongs to our used theme. By activiating the debug mode, i get 3 different error messages (one comming from js_composer / Visual Composer):
Deprecated: The each() function is deprecated. This message will be suppressed on further calls in /var/www/html/wp-content/plugins/js_composer/include/classes/core/class-vc-mapper.php on line 111

I’m not really sure if this one message is the reason for that. The named problem was first seen after updating the WordPress Core to V5.6.2

Any ideas how to fix that?

Best regards