No disconnect event after bond on Android

[Mindaugas]

Hello,

To reproduce this problem I use these steps:

1. Bond to NRF51822 using Android 6.0.1 and latest nRF Connect version;
2. After successful bond, connect to NRF51822;
3. Use "DISCONNECT" button in nRF Connect application;

After these steps my application does not get BLE_GAP_EVT_DISCONNECTED event. As a consequence it does not advertise.

I am using custom board with NRF51822, S130 v2.0.1, SDK v12.1.0. My application has a custom profile. Note: problem is also reproducible with ble_app_hrs_freertos example.

Some insights:

1. If I repeat connect/disconnect action from nRF Connect for few times I eventually get BLE_GAP_EVT_DISCONNECTED with reason BLE_HCI_LOCAL_HOST_TERMINATED_CONNECTION. After that I get disconnect events in application on every disconnect from android.
2. If I turn off bluetooth on mobile phone or reset NRF51822 after bond, I receive disconnect event later on;
3. This behaviour does not reproduce with S110 and SDK v10;
4. This behavior does not reproduce with android version 5.0;

[RichieJH]

I posted something on this about 9 months ago. Unfortunately on certain Android phones it can happen under Android 5.x. One way we get around this is in our Android app we call the peripheral to disconnect, not rely on the Android phone to disconnect. Works a charm and we are no longer subject to the vagaries of Android OS and/or Android phone manufacturers.