Another option is to stop your thread and use hcitcptest to act as the host.
The command hcitcptest is enterd at the command line. just enter hcitcptest without anything else and it will display the options you have (it is a rather small set).
Once connected, you will see a message that arrives in a hex display (I usually pipe the command to less).
If a message arrives, check it carefully to assure the proper encapsulation exists.
This way you are taking any engine configuration out of the equatin just to prove you are getting connected and ar receiving a well formed message.
If everything looks OK, stop hcitcptest and restart your thread. Then you can turn up the engine ‘noise’ level and check the log to see if Cloverleaf (particularly the PDL) complains.
I use hcitcptest with every new connection prior to connecting (and sometimes even prior to configuring) via Cloverleaf.
This gives me the opportunity to detec connection and mesage (inbound or acknowledgment) issues prior to doing any Cloverleaf work – and it removes any vendor assertions that Cloverleaf is the issue since Cloverleaf is not in play.