I'm not exactly sure if this is a bug or not, but the Spirit Bomb continues to grow and charge after the charging bar at the bottom gets completely full. In fact, if you charge long enough, the Spirit Bomb envelops Goku completely. (At this point, I usually turn off Fly so I fall and get out of range, so I'm not sure if the Spirit Bomb would explode on Goku if you launched it.)
If it's a bug, it should be fixed.
If it's supposed to be able to charge and grow past "max", the charge bar shouldn't appear, and you could just assume you can shoot it any time after he finishes talking.
If it's a bug, it should be fixed.
If it's supposed to be able to charge and grow past "max", the charge bar shouldn't appear, and you could just assume you can shoot it any time after he finishes talking.