The girls are no longer on Punishment 4-D at the end of this episode.
When the events of this episode were retold in "The Fate of Bloom" special, the events of the previous episode were not adapted, so instead of the Winx being punished for sneaking into Cloud Tower, the events of them cleaning the school without their powers was re-written as a special assignment for first year students.
This is the second episode with no transformations after "The Black Mud Swamp".
In the 4Kids dub, this episode is known as "Grounded".