we tried to create bond to a ble device, like below
1. bt_initialize()
2. bt_adapter_le_start_scan(__bt_adapter_le_scan_result_cb, NULL);
3. __bt_adapter_le_scan_result_cb scan my ble device
4. bt_device_set_bond_created_cb(device_bond_created_cb, bt_server_address);  
5. bt_device_create_bond(bt_server_address)   (address = 54:A9:C8:E2:AC:C3)

All API calls were successful, but device_bond_created_cb was not called.

also we tried to connect to the ble device,
1. bt_initialize()
2. bt_adapter_le_start_scan(__bt_adapter_le_scan_result_cb, NULL);
3. __bt_adapter_le_scan_result_cb scan my ble device
4. bt_gatt_set_connection_state_changed_cb(__bt_gatt_connection_state_changed_cb, NULL);
5. bt_gatt_connect(address, true);     (address = 54:A9:C8:E2:AC:C3)

All API calls were successful, but __bt_gatt_connection_state_changed_cb was not called.

we look into the document and find no error from above flow, can help to check if anything missing or something wrong.