He was “supposed to”? Not sure where you’re getting that. I don’t think he got any more opportunity pre than post-Jamo’s availability.
Reynolds is the one who really benefitted early from Jamo’s absence in terms of targets. JR got 5+ targets in each of the first 4 games, for 60+ yards in each case. Then Reynolds didn’t get 5 targets even once again til the last game of the season against Minn - and never hit 50 receiving yds again.
They have their reasons, not doubt. Maybe the value KR too much as a punt returner to give him a lot of run as a WR. But I think they’re making a mistake.