I am seeing this message on pages that have third party components loaded. The only change on my system was updating to php 8.1

Deprecated: explode(): Passing null to parameter #2 ($string) of type string is deprecated in \Joomla_4.3\administrator\components\com_fields\src\Helper\FieldsHelper.php on line 59

If I cast string to $contextString the msg goes away but I am not sure if that is the best way to solve it.

public static function extract($contextString, $item = null)
   {
       $parts = explode('.', $contextString, 2);

       if (count($parts) < 2) {
           return null;
       }