Running a Gear VR binary as client will result in a crash shortly after it connects to a listen server. It does not matter whether the server runs on a PC (Windows 8.1) or on another Android device. Connecting with a PC (Windows 8.1) to a Gear VR binary running as listen server works fine. I ran the Gear VR binary on a Samsung S6.
Here (LINK) is the relevant part of a GDB session, showing the traceback.
Without a listen server the Gear VR client will not crash.
After connecting to a listen server a Gear VR client will eventually call FGearVR::DrawDebug() (in Engine/Plugins/Runtime/GearVR/Source/GearVR/Private/GearVR.cpp). That method contains a call to DrawSeaOfCubes() which results in a crash. I expect that the cause is that Canvas->SceneView is invalid at that time, but I have not verified that yet. Anyway, commenting that call appears to have no adverse effects, but makes a Gear VR client run (after connecting) without crashing.
Could you fix that in the next release of Unreal?