A glitch in Harry Potter?

[PeanutButterLips]

Not sure if this has been asked because I know a lot of Harry Potter questions get asked here.
In Harry Potter and the prisoner of Azkaban, Hermione uses the time turner to save Buckbeak. So when Harry was untying the metal chain and Hermione was feeding him ferrets, wasn't Harry, Ron and Hermione watching from the top of the hill?
Because when Buckbeak was executed before she turned the time back, they were watching above. So they must see themselves saving Buckbeak, true?

I think they would have been running up the hill at that time.

I thought they would have got to the top of the hill already because when Dumbledore, the Ministry or magic and the executioner came out, they were still saving him it's only when Dumbledore distracts them talking bout other things they manage to get the animal away

They were walking away. Hagrid tells them not to look back so they don't. They are hurrying and under the invisability cloak. Ron stops to try and stop Scabbers escaping and Hermoine moans that she can't stand it, they're distracted with Scabbers and trying to get away.