I have this error, disappera only when I deactivate the plugin

[11-Mar-2024 20:10:25 UTC] PHP Deprecated: strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated in /home/xxxxx.com/public_html/test14/wp-includes/functions.php on line 7241 [11-Mar-2024 20:10:25 UTC] PHP Deprecated: str_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated in /home/xxxxx.com/public_html/test14/wp-includes/functions.php on line 2187