Ipv6 from Homeassistant changes. thought it is fixed, at least the right part

My Homesssistant runs on an N2. In an (german) Article i find there is an konstant ipv6 Part (Fragen & Antworten: IPv6 | heise online).
With " ip -6 ad sh | grep mng" you should find that. Sadly it didn’t work with homeassistant. But with “ha network info” i could identify one ipv6 beginning with a two that seems to be the right one. In my fritz box i found the same ipv6 as ipv6-gua. the others where ipv6-temp. With this ip i could reach Homeassistant from outside (with some clients) Now, one day later the ipv6 is already not known. The fritzbox shows it but homeassistant doesent. It is not anymore in the list, all ipv6 are completly different. The article says only the left part should change on the fixed ipv6. Is there a way to get such an ipv6 on the Homeassistant on Ordroid N2?

Thanks for any help :wink: