The issue can be replicated 100% of the time.
If I score a goal, the speed debuff sticks on me until I touch the ball again. It doesn't matter how many people touch it in between that period. Changing teams or going spectator doesn't fix it either. This is a pretty big deal for agility builds who need athletics to survive.
After I score a goal, the speed debuff should be removed as soon someone else picks up the ball.