The flayers are not dropping the actual boss rewards. When killing the last one, you get the "end of game" rewards such as the two blues and actual nightfall rewards but the boss engrams don't drop or show up. I've done the nightfall about 7 or 8 times today and that's how it's gone down every single time.
-
Bungie are aware that players are not receiving strike specific loot from this weeks Nightfall and are investigating. https://www.bungie.net/en/Forum/Post/209806134/0/0 [quote][b][u]Strike Specific Rewards: Nightfall Issue[/u][/b] Destiny Player Support is aware of reports that players are not receiving strike specific loot upon defeating the final boss of this week’s Nightfall Strike. Nightfall PGCR Rewards are NOT impacted by this issue, nor is the Vanguard Heroic Strike Playlist. We have forwarded reports to the appropriate party for investigation, and will provide updates when available.[/quote]