Time turner keeps track of its world line for up to 6 hours back. When activated, it creates a branch of the whole Universe inside the past lightcone of the spacetime point on that world line and transports the wearer to that branch.
This seems inconsistent with Harry pranking himself.
This seems inconsistent with Harry pranking himself.
Hmm, I guess the inconsistent part is the original Harry disappearing after awhile...
If I understand your explanation correctly, the inconsistent part is Harry experiencing the prank the first time through the loop.
No, that one is fine, as long as the story is told from the POV of Harry #2