Hope this gets fixed soon, its very annoying.
Looks like isn't fixed till now. I have 3 RPi (1x RPi3B+ lan, 1x RPi3B wifi, 1x RPI4B lan) connected to my router, all with fixed IP. Yesterday I tried some settings in my router and after each router reboot, all the RPi with LE12 lost the connection and needs to be restarted. All devices using latest LE12 nightly... Somebody tried if the LE13 nightly have the same network bug (I will try in the next days, just to have time)?