SteamVR.DeviceConnected events seem not to fire when making builds with cloud build with the latest version of the SteamVR plugin (1.2.1). I’ve noticed local builds have the same issue until upgrading the SteamVR runtime to v1485823399 or higher.
Unity: 5.6.0b10
Build Target: Windows 64-bit
Relevant Plugins: SteamVR v 1.2.1