I am also seeing the same behaviour. Nexus 5X, Android 6.0.1, Pebble Time app 3.9.0-964, Pebble Time firmware 3.9.1. Also tried the 4.0 beta, same results.
Morpheuz works great on the watch, but crashes the PT app when trying to load the settings page.
I'd be happy to provide any information needed to debug.