I have been doing the legend nightfall for this week and at first it seemed to be dropping normally but after a certain point, I seemed to have been getting almost no drops at all (ie. one plat run was a single umbral engram; a second was a single enhancement core; another was straight up no drops from plat rewards). The chest at the end of the nightfall would still work properly but it seemed super out of character to receive nothing or almost nothing at all for a non-matchmade difficulty nightfall.