This episode is one of two from the first two seasons that are unavailable on Disney+. The other is Teasing, which has since becone available after editing of some dialogue.
As is often the case, Lucky's Dad (Pat) is drawn into the Heelers' shenanigans while he's minding his own business and singing a traditional Australian folk song. In this case, he's singing "True Blue," by John Williamson.
No official reason has ever been given for this particular episode not appearing on Disney+.