Weekly Heroic Strike Legendary Engram and Legendary Mark rewards are shared with the Level 41 Prison of Elders weekly activity.
Weekly Legendary Engram and Legendary Mark rewards are shared between Weekly Heroic Strikes and the Level 41 Prison of Elders weekly activities.
Players who have completed their first Weekly Heroic Strike and have not received their guaranteed Legendary Engram reward may have already received it by completing a round of Level 41 Prison of Elders following the weekly reset. These rewards are shared and may be granted from either activity.
For more information regarding weekly rewards, please see: WEEKLY LOCKOUTS AND PROGRESSION RESETS