Missing BLE disconnect event (Supervision Timeout) - nRF9151 + nRF52840

RE: Missing BLE disconnect event (Supervision Timeout) - nRF9151 + nRF52840

Samruddhi Jadhav — Tue, 31 Mar 2026 07:48:36 GMT

Hi Filip,

Thanks for providing the log. I am working on this issue with the team. Please note that there might be some delay in response time due to Easter. You can expect an update by next week. Thanks for your patience.

Best Regards,

Samruddhi

RE: Missing BLE disconnect event (Supervision Timeout) - nRF9151 + nRF52840

tdfilip — Mon, 30 Mar 2026 11:27:13 GMT

I'm forcing the issue to happen by powering off the peripheral device during the connection. It doesn't matter if there is a lot of data to be transferred - no matter what is happening during the connection, if I power off the peripheral device, the supervision timeout doesn't trigger a disconnect event. I've checked it only on one device for now.

When the disconnect event is missing, the central device acts like it's still in connection. Here are the only logs that appear after the issue:

00> [1970-01-01 00:00:51.136000]<err> lpuart: Empty receiver state:4
00> [1970-01-01 00:00:51.137000]<err> bt_driver: Unknown H:4 type 0x00
00> [1970-01-01 00:00:51.137000]<err> bt_driver: Unknown H:4 type 0x00
00> [1970-01-01 00:00:51.137000]<err> bt_driver: Unknown H:4 type 0x00
00> [1970-01-01 00:00:51.137000]<err> bt_driver: Unknown H:4 type 0x08
00> [1970-01-01 00:00:51.137000]<err> bt_hci_core: No connection for handle 1024

Regards,
Filip

RE: Missing BLE disconnect event (Supervision Timeout) - nRF9151 + nRF52840

Samruddhi Jadhav — Fri, 27 Mar 2026 15:47:06 GMT

Hi Filip,

Can you please provide some more details about what is happening on the Bluetooth when this occurs? Are you observing that the link is idle when the link drops and disconnect event is missing? And is there a lot of data transfer happening? Is this issue happening on many devices or is the issue happening on one device? Is it possible for you to provide sniffer log, log or hci-log/uart log between nRF52840 and the nRF91?

Best Regards,

Samruddhi

RE: Missing BLE disconnect event (Supervision Timeout) - nRF9151 + nRF52840

Samruddhi Jadhav — Fri, 27 Mar 2026 14:34:25 GMT

Hi,

I am working on the issue and will confirm it with the team. You can expect an update by early next week.

Best Regards,

Samruddhi