Stelo connection auth failing

[jcbinf]

I am seeing failure to authenticate with Stelo sensor. I have tried sept 19 release and latest nightly plus a local build from source. I have loaded the keks from the QR code using autoconfigure, checked setting per https://navid200.github.io/xDrip/docs/Dexcom/G7.html. Still digging but out of my depth a bit still. Wondering where do those keks keys come from? are they valid? Any suggestions appreciated. See the logcat snip below of failure on my vsmart 341u, android 10 (yes I know it is old and cheap).

11-02 11:25:11.008 7309 8246 I System.out: KEKS-Plugin :: Updating saved key from loaded persistence data
11-02 11:25:11.010 7309 8246 D Ob1G5CollectionService: Changing state from: DISCOVER to CHECK_AUTH
11-02 11:25:11.066 7309 7329 D BluetoothGatt: onConnectionUpdated() - Device=CA:1A:33:26:FA:52 interval=39 latency=0 timeout=500 status=0
11-02 11:25:11.118 7309 19520 D Ob1G5CollectionService: Status: Authorizing 2 11:25
11-02 11:25:11.121 7309 19520 I System.out: KEKS-Plugin :: Changing state: Unknown - > Round Start
11-02 11:25:11.238 7309 8246 D BluetoothGatt: setCharacteristicNotification() - uuid: f8083538-849e-531c-c594-30f1f86a4ea5 enable: true
11-02 11:25:11.240 7309 8246 D Ob1G5StateMachine: Extra data notifications enabled
11-02 11:25:11.336 7309 8246 D BluetoothGatt: setCharacteristicNotification() - uuid: f8083535-849e-531c-c594-30f1f86a4ea5 enable: true
11-02 11:25:11.338 7309 8246 I System.out: KEKS-Plugin :: Processing anext in state: Round Start
11-02 11:25:11.339 7309 8246 D Ob1G5StateMachine: Sending auth command:
11-02 11:25:11.339 7309 8246 D Ob1G5StateMachine: 0x00000000 02 BD 81 7D D0 70 E0 D1 AD 02 ...}.p....
11-02 11:25:11.438 7309 8246 D Ob1G5StateMachine: Received Authentication 2 indication bytes: 03E64488E11E526EBED3F6295CEC7E96B1
11-02 11:25:11.438 7309 8246 I System.out: KEKS-Plugin :: Received remote response: 03E64488E11E526EBED3F6295CEC7E96B1 when in Request Auth
11-02 11:25:11.439 7309 8246 I System.out: KEKS-Plugin :: Processing anext in state: Request Auth
11-02 11:25:11.440 7309 8246 D Ob1G5StateMachine: Sending auth command:
11-02 11:25:11.440 7309 8246 D Ob1G5StateMachine: 0x00000000 04 BC 22 98 36 2D 15 42 F2 ..".6-.B.
11-02 11:25:11.532 7309 8246 D Ob1G5StateMachine: Received Authentication 2 indication bytes: 050201
11-02 11:25:11.532 7309 8246 I System.out: KEKS-Plugin :: Received remote response: 050201 when in Challenge Reply
11-02 11:25:11.532 7309 8246 I System.out: KEKS-Plugin :: Could not authenticate!
11-02 11:25:11.532 7309 8246 I System.out: KEKS-Plugin :: Changing state: Challenge Reply - > Unknown
11-02 11:25:11.532 7309 8246 I System.out: KEKS-Plugin :: Processing anext in state: Unknown
11-02 11:25:11.532 7309 8246 D Ob1G5StateMachine: Null value returned via plugin
11-02 11:25:11.532 7309 8246 D Ob1G5StateMachine: Attempting state reset
11-02 11:25:11.532 7309 8246 D Ob1G5CollectionService: Resetting internal state by request
11-02 11:25:14.807 7309 7329 D BluetoothGatt: onClientConnectionState() - status=19 clientIf=5 device=CA:1A:33:26:FA:52
11-02 11:25:14.809 7309 7329 D Ob1G5CollectionService: Connection Disconnected/Failed: com.polidea.rxandroidble2.exceptions.BleDisconnectedException: Disconnected from MAC='XX:XX:XX:XX:XX:XX' with status 19 (GATT_CONN_TERMINATE_PEER_USER)
11-02 11:25:14.814 7309 7395 D Ob1G5CollectionService: Bluetooth connection: Disconnecting

[Navid200]

Post a screenshot of the status page.

[jcbinf]

After grabbing one screenshot, while checking it on the phone, the Stelo sensor spontaneosly paired with chimes and everything. I did not instigate the action myself, and did not interact with anything other than the Files app. I made another screenshot immediately; thus 2 posted.
I got an entire 24 hours data downloaded from the sensor, and for now the app appears to operate as expected.
This after 3 days of uncounted restarts, setting experiments, installing variuous builds...
Perhaps something is flaky with pairing on my device?
I am going to continue trying to figure it out.