While it might be mismanagement of that specific one player, it may be better for the roster and team to move him around, or even for that player because it gives him a job.
Meaning, if Moats were playing DE (perhaps the position he's best suited for) he likely wouldn't be on the roster at all due to the depth they have. Moving him to OLB doesn't give them the best Moats has to offer, but they keep Moats and he gives them a better depth player at OLB than what they had at that position and a guy to play specs.
Spencer Johnson working at 34 OLB was odd, but I recall them mainly playing him as an edge player, not in coverage where he'd be a severe liability. So basically playing the role of a 43 end.
I only recall Carrington playing OLB in practice, not in games, perhaps he did, I dunno. But if he did I assume it was in the same capacity as Spencer. I only recall him playing 34 DE after Kyle Williams went out for the year.