SLZB-06 - WiFi settings deleted after core upgrade

I have my Zigbee coordinator SLZB-06 in my living room connected via WiFi. Last Sunday, HA couldn’t display the states of my Zigbee devices.
I also couldn’t see my SLZB-06 on the network anymore. After connecing it via ethernet, I noticed that there had been a core update of the SLZB-06 and all the WiFi settings were deleted. Is this normal?
I also cannot see a setting where I can choose to not automatically install core firmware updates. I can connect the coordinator via wired LAN, but then I am less flexible in placing it in the middle of my living room.