When simulating a rewind media command (ie. Skip back 10 seconds) either from a remote device or a button on the phone, that cmd gets registered only once in PA. The second command doesn't work. There's a simple way to test this.
1. Install this free app https://play.google.com/store/apps/details?id=flar2.homebutton
2. Map any button to perform a Rewind cmd (here I chose Single press Volume up button Button mapper https://imgur.com/gallery/9Clqd6K)
In most music players (Gonemad, Jetaudio, Musicolet, etc.) pressing that button multiple times in a row will continuously rewind. In PA, it'll rewind only once.