Not an exploit of the game or a bug, but still a new way of forcing damage from the opponent, that has become really popular recently.
What you need to do is land a command grab with Makoto. As soon as the grab finishes, do another command grab before the other player does anything.
This will put him in a position where he was expecting a hit but gets grabbed instead. As soon as your grab finishes, do another one again.
This will again put him in a position where he was expecting to finally be hit but gets grabbed.
By this time, he should be expecting an additional, fourth grab after your third grab. Proceed to your usual post-command grab combo and profit.
This trick will allow you to steal about 2 jabs of life from the other player. It has become kind of common now and should be used from moderate to high frequency by Makoto players, giving them a way to “steal” damage in the game.