This has nothing to do with position it's like he lost his entire passion for football. Can't understand what happened to him. His body language is horrible, like someone is forcing him to play.
His dream was to play for Barca and he now looks lost. Something went wrong but but what? Maybe he has some personal issues.
I think his personal issue is Valverde - personally.
Coutinho doesn't know what to do, what he is expected to do, he plays in a nowhere-man's position, without any confidence whatsoever.
There is an old saying or rule among coaches and I think the problem must be somewhere there...
There are
non-creative players (still great players with different advantages) and
creative players.
I think we should agree upon that Coutinho is a creative player.
One
cannot really coach or instruct a creative player, because he will very soon lose his creativity!
When indsructions are given too often, he will lose his spontaneity, his unpredictability, because instead of improvising, he wants to do whatever he was told to do.
And it is specifically the case if the creative guy is not a trusted regular starter.
These "artists" need to play more or less instinctively, there are enough other players remaining in a team who are good tactical machines.
What I suppose is that EV instructed and wants to instruct Coutinho too much, too intensively, wants to rule and form his game, and that's why Coutinho plays badly, without any belief or confidence.
Too much training might ruin a player's physical body. Too much instructions might mix up his entire footballing brain...