This bug I already encoutered twice in FM19. Yet in FM23 it can still happen, see screenshot.
No matter what Role I give him on the midfield he gets a half star, while in fact he is 4 stars.
When I put him in this position I keep on getting the message in game "played out of his position". This does not improve over matches.
I had the same issue in FM19 where my 5 star Left Back all of a sudden went to half a star and the same message would appear.
Please fix this issue.