I am at light level 600. My "Powerful Rewards" are dropping at 602. WTF? Bungie is slowing power progression for the Black Armory to drag this out as long as possible.
It's been the same since forsaken released. The powerful gear drops a a level corresponding to the power level of the activity. Like last wish is 580 ish so after 580 you'll only see small increases. I completed the forge and got the auto rifle frame completed and they dropped much higher than my current light. (I was 606 the lmg dropped 613)