Firstly, this is only a warning that the use of 3rd-party output buffer handlers “could” interfere with the scan, not that it absolutely will. So you will need to asses whether or h=not this particular OB handler is a problem for you.
Any custom OB handler that intercept the output on your wp-admin pages can affect the performance and even alter the output of those pages. Then other developers, like myself, can no longer guarantee that the output on our plugin pages is generated by our own plugin’s code. In other words, you are now dealing with a middle-man that can alter the results on the page beyond the original author’s control. I personally don’t think it is appropriate for anyone to invoke a custom OB handler on some other plugin’s wp-admin pages.
As for what you can or should do about this, it will require some testing on your side. First, you can just deactivate that Litespeed cache plugin temporarily, then run the Complete scan with that warning message gone to measure the baseline performance and output results from my plugin. Then you can re-activate that plugin and run the complete scan again to compare. If there is no difference then it may be alright for you to keep it enabled while running scans. You could also look for a way to disable any output filtering on your wp-admin URL within the settings of the Litespeed cache plugin, or ask the developers why they are invoking a OB handler in the wp-admin at all, as they are presumable using it for caching and you should never cache the wp-admin pages anyway (firstly because it could be a potential security risk to cache anything that a privileged admin user sees while logged into your wp-admin, and secondly because the wp-admin displays dynamic pages which would be ineffective and inaccurate if they were cached).
Please let me know if there is anything else.
