Debug.log: PHP Warning: Cannot modify header information - headers already sent

Using Comet Cache Pro, I’m getting hundreds of the following warnings built up in the debug.log

PHP Warning:  Cannot modify header information - headers already sent in /home/site/public/wp-content/plugins/comet-cache-pro/src/includes/traits/Shared/HttpUtils.php on line 175

I’m using this plugin with s2member pro if that helps.

Thanks.