How a tank swap becomes a clusterf#ck: Tank 1 has tons of threat, tank 2 does not. Tank 2 provokes and follows with a threat move but in the mini gcd between the two, tank 1 smacks target again and stays above the other tank.

If you really want to swap cleanly, stop generation before the swap and sheathe your weapon during the actual swap. After the other tank gets hate, give them a gcd or so to solidify their lead over you.