@filippodicostanzo - apologies for the delay in response. I have been focusing primarily on iOS and hadn't tried things in an Android emulator in a while.
I just spun up an SDK23 emulator (which should be supported) and unfortunately I appear to have the same issue as you and @jfbguy are encountering. Neither the getCurrentPosition or watchPosition are returning valid data.
Hope someone addresses this soon (or finds a viable workaround)!