Hello all,
First of all I have the regular iWatch 3 and iPhone SE.
I have the same problem as all of you. I've purchased my Apple Watch 2 weeks ago and 3 days ago my watch starts with this problem. So I'm going to explain what is happening exactly:
If I open music app on my watch and I select a playlist located on my iPhone, it shows the song as playing but 3 seconds later disappears the title of the song and nothing is playing.
Then I start playing a playlist choosing it on iPhone, so I open the app on iWatch and it shows as playing the currently song without problems, also I can control de volume, skip songs (on the same playlist), etc... The problem is, if now I want to choose other playlist, then stops the music and disappear again the title.
I think this problems happened when I have updated the software because it started happening the same day as I updated it.
I have to add that I've tried all the ways that all of you posted here: turn off and on iWatch and iPhone, unpair and pair again, disconnect Bluetooth, delete all playlist on iPhone and syncing them again...
If someone know a way to fix it, please let us know.