Historical Rules · 11 November 2016
Rule 712.4
Official source text from the 11 November 2016 Rules release
If a melded permanent leaves the battlefield, one permanent leaves the battlefield and two cards are put into the appropriate zone. Example: Chittering Host, a melded permanent, dies. An ability that triggers “whenever a creature dies” triggers once. An ability that triggers “whenever a card is put into a graveyard from anywhere” triggers twice.