IPv6 connectivity issues: streaming stops

[fabricist]

Describe the bug
IPv6 connectivity issues: periodically loosing IPv6 address, this leads to the streaming of music (via Airplay) to stop.

HiFiBerryOS version
20221128

HiFiBerry sound card
DAC2 HD

To Reproduce
Steps to reproduce the behavior:
In an IPv6 enabled network, with SLAAC assigned addresses and periodic RA from the gateway/router: Start streaming music over airplay from an iOS device (also with an IPv6 address configured) at a moment when the hifiberry-os has an IPv6 address. Streaming works until the IPv6 address is lost, at this moment the streaming stops. If the streaming is started when there is no IPv6 address, IPv4 will be used instead, and no problem occurs.

Expected behavior
Streaming of music does not stop, even with IPv6 connections.

Additional context
I investigated this problem, and it seems to me that the hifiberry-os suffers from a problem in systemd networking, this report describes the same problem I am seeing: https://bbs.archlinux.org/viewtopic.php?id=269099

I can see the IPv6 address that comes and goes, alternating with each unsolicited RA that arrives.
Apparently it is solved now in systemd (by systemd/systemd-stable#111)

Unfortunately I am not able to confirm what version of systemd is in hifiberry-os

Of course if streaming is started when hifiberry-os has no IPv6 address, the connection is established in IPv4 and it remains that way for the entire streaming session. So in this case everything is working. In the end the problem is very intermittent and it was difficult to track it down.

[hifiberry]

Please try the latest HBOS64 release as it uses a newer systemd version
https://github.com/hifiberry/hifiberry-os/releases/tag/64alpha7