[John James Jacoby]

Until we fragment cache the bp-default template, this could be an issue in a few places. The way we combated it on testbp.org is to set the cache to refresh every 5 minutes. Not perfect, but it works for now.

Looking at your site, do you have it caching for logged in users also? Obviously a majority of your traffic with BuddyPress is from logged in users, but all of the activity based bits are hard to cache dynamically until we can tell w3tc which parts to cache, and which are activity sensitive and to skip.