Appeal play

[dmore]

I don't understand why this situation is considered part of an appeal. They both sound like the standard interpetatoin of the live ball handling of a caught popup.

Runner leaves, fielder catches the ball, runner heads back to third. If you tag the runner or the base before they gets back, the runner is out. Doesn't matter if the contact with the base is "inadvertent" or not.

THis is only an appeal if that runner advances and doesn't go back. Then they have to execute the appeal.

Am I missing something here?