Android always prefers ZT address even in local LAN

I have followed the advice here to adjust the ip range to /23, so the local ip address of an Android client (eg. is always preferred, when connected to both ZT and local LAN.
But when my Android phone is connected to both ZT (10.10…) and my local LAN (192.168…), in the beginning it always prefers the ZT IP address instead. So I cannot even ping the router (in or any of the other devices connected to LAN.
Only after a GREAT amount of time I’m able to ping the other LAN devices. I don’t know when or how this happens, but it’s definitely not normal behavior.
This is a bug in the Android app and has prevented me from using ZT for over a year.