I'm loading DataTable2 after Scribunto, both extensions show up in the versions page, mw.ext.ParserFunctions does exist.
Topic on Extension talk:DataTable2/Flow
I think this has to do with the check
if ( isset( $wgExtensionCredits['parserhook']['Scribunto'] ) ) {
wgExtensionCredits doesn't appear in the Scribunto code