BC127 Audio during call

Hi, I have been trying for ages to figure out what audio signal gets routed during a call.

I have my BC127 set up as AGHFP and paired to a speaker,
I have a second device paired and using A2DP to stream music from the analog input.

When I send the command for incoming call, I hear the beeps, and send the call answer command.
I then hear a couple of clicks just after the stream gets paused, but I am unable to figure out what is getting routed to the HFP.

My goal is to have some audio going into the bc127 analog in, and initiate a call on the hfp device to hear that audio.

Ver-
Sierra Wireless Copyright 2018
Melody Audio V7.3
Build: 1544637564
Bluetooth addresses: 20FABB043667 789D0BF5585B
Profiles: A2DP AVRCP AGHFP BLE SPP PBAP MAP
Codecs: SBC

Hi RawLiquid,

Could you please help to draw a simple topology of your case so I can figure it out?

Thanks,