zephyr: LE Audio: Controller: Failed to establish a second CIS with Packetcraft controller

Describe the bug The PTS tests with 2 CIS fails because the second CIS could not be established. Looking for an explanation I tested samples/bluetooth/unicast_audio_client app with samples/bluetooth/unicast_audio_server app on nrf5340dk boards, with 2 bidirectional CISes configuration, switching between Zephyr and Packetcraft controller.

There is no problem with second CIS when Zephyr controller is on both sides of a connection. But in Zephyr <-> Packetcraft connection the second CIS always fails to be established. Is there a known solution for this issue?

Btmon logs unicast_client_zephyr.log unicast_server_packetcraft.log

To Reproduce Unicast Client: Zephyr Host + Zephyr Controller: In samples/bluetooth/hci_rpmsg, build the netcore binary:

west build -b nrf5340dk_nrf5340_cpunet -- -DOVERLAY_CONFIG=nrf5340_cpunet_iso-bt_ll_sw_split.conf

Flash the controller with: west flash --recover

In samples/bluetooth/unicast_audio_client build the appcore binary: unicast_client.config.txt west build -b nrf5340dk_nrf5340_cpuapp . -- -DOVERLAY_CONFIG=unicast_client.config.txt

Flash the app with: west flash

Unicast Server: Zephyr Host + Packetcraft Controller: Download the controller binary: https://github.com/nrfconnect/sdk-nrf/blob/v2.4.99-dev2/lib/bin/bt_ll_acs_nrf53/bin/ble5-ctr-rpmsg_3393.hex

and flash with: nrfjprog --program *.hex --chiperase --coprocessor CP_NETWORK -r

In samples/bluetooth/unicast_audio_server build the appcore binary: unicast_server.config.txt west build -b nrf5340dk_nrf5340_cpuapp . -- -DOVERLAY_CONFIG=unicast_server.config.txt

Flash the app with: west flash