Wikimedia Bugzilla is closed!

Confirmed.

Is this still present on master?

Yes (or at least the offending code is still present on master) Just noticed the same bug myself. The problem is in SMWQueryResult::getQueryLink() This functions starts with calling getLink() but then duplicates the same code itself. The relevant lines are:

               $params = array( trim( $this->mQuery->getQueryString() ) );

                foreach ( $this->mQuery->getExtraPrintouts() as /* SMWPrintRequest */ $printout ) {
                        $serialization = $printout->getSerialisation();

                        // TODO: this is a hack to get rid of the mainlabel param in case it was automatically added
                        // by SMWQueryProcessor::addThisPrintout. Should be done nicer when this link creation gets redone.
                        if ( $serialization !== '?#' ) {
                                $params[] = $serialization;
                        }
                }

These lines should be removed from either getQueryLink() og getLink()

Code mentioned by comment 3 is part of SMW, not SM.

Cannot easily improve this due to lack of tests and the relevant APIs being virtually untestable. Need to have some things cleaned up in SMW to mitigate this...

Also, the solution provided in comment 3 seems highly suspect to me.

https://github.com/SemanticMediaWiki/SemanticMaps/issues/12