ALF for Android - 'Send' via Bluetooth fails when ALF is running in the background

Question
With the app in the background, when attempting to send a form to ALF V 1.4.0.555 using the 'Send' pidget via Bluetooth, the pen vibrates twice after the pidget has been ticket, then 1 second later, the pen vibrates 'hard' once. The form is subsequently not communicated to the ALF router. Why?

Answer
This error occurs only when the ALF app is running in the background on Android OS 5.1.1 - once the app is opened, and the Send-pidget ticked again, will the form(s) be routed successfully. This is a known issue created by Android in this release of their product; OS releases prior to and after version 5.1.1 do not have this issue. 
There is currently no available fix for this issue beyond making sure that the ALF app is active and not running as a background task when the form is sent to the Android mobile router from the pen.