Errors with non-existent files.

I’ve got this plugin working on 4 of my sites, but the 5th keeps getting errors. I uninstalled wp-super-cache and verified it’s files no longer exist on the server. No backup is generated.

[2017-09-22 19:55:34] xcloner_api.INFO: Processing ajax request ID _d27gz1flk [] []
[2017-09-22 19:58:24] php_system.INFO: E_WARNING: array ( ‘type’ => 2, ‘message’ => ‘unlink(/path/to/site/wp-content/cache/supercache): Is a directory’, ‘file’ => ‘/path/to/site/wp-content/plugins/wp-super-cache/wp-cache.php’, ‘line’ => 168, ) [] []
[2017-09-22 19:58:32] php_system.INFO: E_WARNING: array ( ‘type’ => 2, ‘message’ => ‘include(): Failed opening \’/path/to/site/wp-content/wp-cache-config.php\’ for inclusion (include_path=\’.:/usr/lib/php:/usr/local/lib/php\’)’, ‘file’ => ‘/path/to/site/wp-content/plugins/wp-super-cache/wp-cache-phase1.php’, ‘line’ => 7, ) [] []