On another one of our sites (http://brothersinslaw.com) we now get a similar message but it references a different output buffer.
Another Plugin or Theme is using ‘ct_inject_nocache_script‘ to handle output buffers.
This prevents actively outputing the buffer on-the-fly and will severely degrade the performance of this (and many other) Plugins.
Consider disabling caching and compression plugins (at least during the scanning process).
Any help or insight on these similar issues would be appreciated.