Bluetooth disconnecting after 1 second

Oh, interesting. I was not using Bangle 2 but other board. With Bangle 2 I see the same issue

=Promise: {  }
BluetoothRemoteGATTServer: {
  "device": BluetoothDevice: {
    "id": "60:55:f9:79:a7:2a",
    "gatt":  ...
   },
  "connected": true, "handle": 0 }
connected
disconnected (62) after 0.99880981445 secs

however it is inconsistent, when I try second time it often works.
I do not 'upload to ram' I just copy paste( ctrl+v) that code into left side and then just press up key and run it again