Sometimes, the cached page (located in /wp-content/cache/page_enhanced/[sitename]/) contains HTML entities in the post content, which causes any HTML code in the post content to be output to the page rather than rendered as HTML as intended. This happens for both Basic and Enhanced caching methods.
This only occurs on HTML in the post content, and only occasionally. Clearing the cache removes the problem temporarily, but it eventually returns.
This is a little tricky to explain, so I uploaded a screenshot of the problem here: http://postimg.org/image/lxodrmk47/
I have another WP site on the same server running W3TC with no issues.
Any ideas? Thanks very much in advance.