Bluetooth disconnecting after 1 second

for me it mostly works even with Bangle, when it disconnects in 1 second I see on arduino side that it did not notice the connection at all. Googled it and found one explanation

The error code 0x3E means "failed to establish". The BT core spec states that if a master does not receive a packet from the slave within the first 6 connection events after sending a connection requests then the master considers the connection lost.

You most likely are getting this because your slave device is not receiving the connection request, and therefore is just continuing to advertise. The master then tries 6 connection events and never gets a packet.

I think this is what happens here Arduino side is ignoring the connection attempt.
I build the example with Tools -> Core Debug Level -> Verbose and I see lot of info when connection is estabilished but in this case when it does not work I see nothing on Arduino side