While I am not using USB-C earbuds, I am having the same issue.  I was able to skip songs using the control on the wired earbuds, but it stopped working after the last update.  I updated Pandora again today and the problem still exists.  I did my own troubleshooting and the skip function works when using YouTube on my phone and it works on my old iPod.  That means the problem is with the Pandora app.  No one from Pandora has been able to offer solutions other than suggesting the problem is with the phone.  It's not the phone! ... View more