Some “microformats2” themes or plugins always add e-content as a “post class.” In combination with some of IndieBlocks’ blocks, which “produce” their own e-content, this leads to 2 e-contents: one which corresponds with the post as whole, and a second one which contains only the block’s children. (Microformats clients will likely just disregard one of them, so no real harm done. But you might be able to tweak your theme’s post_class filter and avoid this.)
