Erik, one thing I notice in the log is that the rest message appears to be null:

REST Msg Outbound - RESTMessageClient : Executing: Outbound REST Message/Method: null/get

Are you sure you're accessing the Rest message correctly by name? One thing to keep in mind, if this is part of a scoped application you might need to reference the rest message by it's scoped name e.g. "x_acme_myapp.Device42".