No sound on my second Raspberry Pi4 with my multiroom setup - (Alsa) Failed to get chunk

Hello,
I have two Raspberry Pi 4, one with 4 GB of RAM, and the other with 2 GB of RAM. I use Balena Sound for multi-room broadcasting. The Raspberry PI with 4 GB RAM is the “master” computer, the one with 2 GB RAM is the “slave” computer. On these two machines, I installed with the “production” edition the OS balena OS 2.83.10+rev1, Supervisor version 12.9.3. I transmit my music with an Android smartphone via a Blue Tooth Tp-Link UB400 dongle, which is connected to the “master” computer, the Raspberry PI with 4 GB of RAM. I use the simple audio output of the Raspberries to listen to the sound.
When I turn it on, everything works fine, but after a while, the “slave” computer does not emit any sound. Looking at the terminal of this computer via the balena dashboard, there is informations such as :

multiroom-client 2021-10-26 16-50-34 [Info] (getPlayerChunk) Exception

  • multiroom-client 2021-10-26 16-50-34 [Info] (Alsa) Failed to get chunk*
  • multiroom-client 2021-10-26 16-50-39 [Notice] (Alsa) No chunk received for 5000ms. Closing ALSA.*
  • multiroom-server 2021-10-26 16-52-17 [Info] (do_read) next read < 0 (balenaSound): -14.886 ms*
  • multiroom-client 2021-10-26 16-57-00 [Info] (setDiffToServer) Last time sync older than a minute. Clearing time buffer*
  • multiroom-client 2021-10-26 16-57-00 [Info] (Alsa) frames: 1323*
  • multiroom-client 2021-10-26 16-57-00 [Warn] (Alsa) snd_pcm_avail_delay failed: I/O error, avail: 2645, delay: 5249, retrying.*
  • multiroom-client 2021-10-26 16-57-00 [Info] (Alsa) Failed to get chunk*
  • multiroom-client 2021-10-26 16-57-05 [Notice] (Alsa) No chunk received for 5000ms. Closing ALSA.*

I have done an interesting experiment. I reversed the roles of the two Raspberry pi. The Rpi4 with 2 GB RAM became “master”, the one with 4 GB RAM became “slave”. And I have the same problem but in the other direction. The Rpi4 2GB RAM works perfectly while the Rpi4 4GB RAM has the same problem as the previous experience.

What can I do to fix this?
I had installed a newer version of balena OS (2.85.2+rev3; Supervision version: 12.2.11) but the “master” computer could not recognize my Blue Tooth Tp-Link UB400 dongle.

I hope that the explanation of my problem is clear.
Best regards,
Keng-Waï