You, me, and 10 millions others, bro!
I'm not sure this will help, but... Do you have a rip of the Zepplin CD that you made? Or are you adding from the Apple Music service? Last I checked, Led Zepplin was only on Spotify, though maybe that changed. Are all the other tracks actually Zepplin? If it was actually your own CD, all I can think is that when you linked up to the cloud for Apple Music, Apple conveniently replaced its version of "Whole Lotta Love", which would be by a cover band, since they don't have Zep.
If this is what happened, how do you fix? All I can think of is turning off the cloud, making sure that the correct WLL is on your hard drive, and starting over.