ble_app_peripheral GAPC_PARAM_UPDATE_REQ_IND

Hello
I am using ble_app_peripheral as the basis of my application
There are a lot of other changes I have made to the basic ble_app_peripheral sample code but I think they won't be relevant to this particular question

After connection between smartphone and the DA14580 development board, the board stops BLE advertising
After about 10 seconds of this, I notice GAPC_PARAM_UPDATED_IND message is always generated