Error log at class-cache-master.php on line 713

Hi,

When I activated the plugin, I will get a lot of error log like this:

[23-Dec-2020 02:30:32 UTC] PHP Warning: strpos(): Empty needle in /home/site/address/wp-content/plugins/cache-master/inc/class-cache-master.php on line 713

When I finish all setting and enable cache, it works but still have the error nonstop.