Docker IPV6 address

Hi
Using docker under unRAID
Until latest version (20.10.17) my containers got IPV6 address based on the dynamic prefix and a suffix of the container mac address (eui-64).
After the update, the container get IPV6 based on the dynamic prefix and ::2/::3 (etc) suffix.

How do I restore previous behaviour?

Thanks in advance

Any help would be appreciated