Injuries of some extent to Jones, Shaw, Smalling, Carrick, Young, Fellaini, Lingard, Van Persie also tend to make team cohesion under a new manager tough..
The problem is that too many are going forward so you end up with only 2 players back. the other team then counters quickly and there isnt much that the 2 cbs can do because they are outnumbered
and to an extent, that is LVGs fault. Playing a midfield diamond means the width has to come from the fullbacks and leaves the 2 CBs exposed. Hence why having 3 CBs worked for his Dutch team.