This happened twice to me today. Both times I had just set the power of a swing and the meter just disappeared instead of starting to move right.
The second time it was a putt; I can't remember what kind of shot it happened on the first time. Closing and reopening the game client was the only solution; the entire interface was frozen because it was the middle of a shot.
And now it happened a third time, again on a putt, same round as the second incident.