Wierd issues after upgrade on 22.03 for Mi Router AC2100

Hi guys, I have a Mi Router AC2100 for testing which was runnng the latest official 21.02.3 release just fine as an AP connected to a main router via lan interface. The config changes from defaults were only:

  • change default IP address and subnet from -> 192.168122.250
  • set static default gteway and preferred DNS server for lan interface to
  • set DHCP server onthe AP to ignore lan interface
  • enable wireless

Yesterday I did a sysupgrade to openwrt 22.03.0, settings were retained but I found some big and wierd issues:

  • the AP couldn't communicate at IP layer anymore with the upper router
  • wireless STA devices (with any kinf of authentication, Open, WPA-PSK, ...) connect fine but
    -- qualcomm's androids disconnect soon after, both with and without DHCP
    -- realtek's windows stay connected but couldn't reach AP IP even when static IP
  • wired devices connected to other AP lan ports got DHCP address assigned but couldn't communicate with the upper router

I was able to make a little step further by issuing an arping from the main router to the AP IP which somehow unlocked IP communication between AP and main router but all the other issues were still there.

I assumed something could have got wrong during sysupgrade so I attempted a reset. After reset I enabled wireless only and tested the wifi link from anndroids and it kept connected, also the wired device connected to the AP acting as DHCP server were fine and seeing thee wireless ones. However, redoing the above changes put me in the same situation. I finally reverted to 21.02.3, did the same changes again and now it's working as before.

Where do you think the bug could be?