It is speculation and rumours.
If and in my experience as a team leader, disagreement doesn't mean a falling out.
You practically live and work in the same room, on the training ground, eat together, travel together, hotel together, work together.
They have to be on the same page, in meetings, etc. Put an unity into the players, gain the dressing room.
There can be no other voice in the dressing room, only the manager/team leader.
There should be no disrespect towards the manager or of his methods.
Not done in my playing days, shouldn't be done in pro football, you stick to the plan!
You do your job on and off the pitch!