I was in a similar situation, with Garmin Connect on my Android phone and wanted to also have it on my Android tablet to benefit from the bigger screen.
I don't remember exactly what went wrong but I gave up trying. I think you cannot add the Garmin device from more than one mobile device. So I would've had to e.g remove the EE2 from the app on my phone in order to be able to use it with my tablet.
But maybe I missed something or am mis-remembering it.
