tested the patch
and it makes things a bit better.
> rcwicked status
Apr 20 10:22:41 beagle systemd[1]: Starting wicked managed network
interfaces...
Apr 20 10:23:11 beagle wicked[13745]: device wlan0: operation timed out
Apr 20 10:23:11 beagle wicked[13745]: lo up
Apr 20 10:23:11 beagle wicked[13745]: eth0 up
Apr 20 10:23:11 beagle wicked[13745]: wlan0 setup-in-progress
wlan0 is up, but not associated.
after using my manual setup script
#!/bin/sh
iwconfig wlan0 ESSID wlanbridge mode ad-hoc key 1234567890 channel 7
ifconfig wlan0 192.168.12.2/24 up
then I can do ifdown wlan0 ; ifup wlan0
and it still works.
btw: I see wpa_supplicant running - maybe it is disturbing things?