Apple has released the fourth beta of watchOS 6 to the developers

General
Resolved Issues
When playing audio in Music, Podcasts, or Books on iPhone, the counterpart watchOS app launches as expected to the Now Playing view. (51591666)

Reinstalling built-in apps reinstalls both the iOS app and the watchOS counterpart app. (50799441)

Close buttons are positioned correctly in modally presented interfaces. (51679414)

Apps can consistently send data over WatchConnectivity. (51653277)

  watchOS 6 Beta 4 released