Post tackle when opposition players engage to form a ruck and in the act of driving the opposition the the opponent yields goes backwards thus causing the the winning player to go to ground despite winning the battle.
Could you give an interpretation on this as the law refers to intentionally (I think) going to ground.
If I understand your question correctly this is ruckers driving over and going to ground from their own momentum, versus them going to ground through being pulled over the ruck by the defenders.
In the first case where a counter ruck goes over the ball but then goes to ground The Rugby Ref would be looking for the grounded player to move away pretty swiftly. If the lie over the ball and kill the contest then they are going to be penalised for going to ground.
In the second case where a defender at the ruck pulls an opponent over the ruck and onto the ground The Rugby Ref would again be looking for the grounded players to move away to allow play to continue. However The Rugby Ref would not penalise the grounded player, but would caution the defender not to pull players over the ruck, but instead to bind on and push. The ruck is a pushing contest not a pulling contest. If the defender failed to heed the warning he would be penalised for failure to bind in the ruck. If a defender is pulling a player through the ruck he is part of the ruck but is not bound to anyone. A bind must be from armpit to wrist.
The Rugby Ref