In UserProfileHooks.php, the function onDifferenceEngineOldHeader() and onDifferenceEngineNewHeader(), the $oldHeader and $newHeader construct the header with <h4> instead of <strong> (MediaWiki default behavior), causing RevisionSlider fails to select the element.
Topic on Extension talk:SocialProfile
Appearance
Thanks for the very useful bug report and research! :) I've submitted a patch based on the information provided to gerrit; give it a spin and let me know if it fixes the issue and I'll be happy to +2 the patch and have it land on master to fix the issue for all users.
That's exactly what I've done to my installation. It works.