Hi @Solla-topee , thanks for looking at this report.

As already mentioned in the initial post, the model is wpa4220v4_eu (hardware V4). I tested two devices of that same model and they behaved the same.

I didn't record a wireshark trace but I remember it very clearly. When roaming from the main wifi router to the WPA4220 wifi, only the device just switched is affected, other devices are not affected. After switching to the WPA4220 the device that just switched immediately sees all a lot of traffic but it must wait about 5 minutes before seeing any unicast traffic to itself. After 5 minutes everything works fine.

My main router has a "broadcast" DHCP option that was off by default, that really helped identify the problem. Before I turned it on I had to wait 5 minutes to get an IP address. After I turned "broadcast DHCP answers" on I get an IP address immediately - but still no internet, still have to wait for 5 minutes for unicast packets.

The problem does not affect "wired roaming", it affects only wifi roaming. In other words, if I turn off wifi then I can connect, disconnect and reconnect an Ethernet cable back and forth between the main router and the WPA4220 and everything works immediately.

This all took me hours to isolate and understand but once you understand the problem this roaming test is really very easy to perform, it's one of the most basic tests that should be part of your QA.