PHP Warning: count():

We’re receiving these PHP warnings in our error.log:

[23-Jan-2018 06:11:10 UTC] PHP Warning: count(): Parameter must be an array or an object that implements Countable in /home/server/public_html/mywebsite.com/wp-content/plugins/cloudflare/src/WordPress/Hooks.php on line 133

Vaguely similar to this: https://ww.wp.xz.cn/support/topic/constant-bad-requests/

The function is shown below:

  public function purgeCacheByRevelantURLs($postId)
    {
        if ($this->isPluginSpecificCacheEnabled()) {
            $wpDomainList = $this->integrationAPI->getDomainList();
            $wpDomain = $wpDomainList[0];
            if (count($wpDomain) <= 0) {
                return;
            }

The error does not trigger when ‘Automatic Cache Management‘ is set to ‘Off‘.