The current implementation of transient caching always looks for the post ID when the_content filter is applied. This ends up causing problems when the_content filter is applied to other text that is displayed on a page along with the post content.
janw.oostendorp proposed using a hash of the content being filtered instead of the post ID. I think this sounds like a pretty good solution.
Use a hash of the HTML as an identifier, insted of content type, page…
… etc. re: issue #31 hat-tip to janw.oostendorp
Closed with version 1.3.3