It’s hard to say.
Your group will have to make a judgment call. To demonstrate “full control of balance” the player must perform some action that breaks up the flow of movement toward the target after release, before proceeding toward the target. Some examples of actions that demonstrate balance might be: (1) a clear pause and display of balance, (2) placement of the back foot on the ground behind the mark, or (3) retrieval of the marker disc. The key to all of those is to show balance and control of your body behind the mark before moving forward. The best course of action is to leave no room for doubt, which is easy to do if you are indeed in control of your body after you’ve released the putt.