Stephen,
I made a simple example. An empty screen with an action button. The sub-action is a transmit. There is no main fetch in the application. Therefore, the sub-action does minimal thing.
Yet in this case, if the action button calls transmit for twice, the Android client crashes.
The behavior is the same in 6.0.46 which I got today on a Android 4.4.4 tablet.
-Yang