Here as we tested, sometimes it shows IPv6 "Supported", and sometimes "Not supported".
IPv6 is supported by Chromium all the time, but it has a fallback mechanism.
When certain timeout is reached, Chromium will fallback to use Ipv4.
In brief, Chromium uses IPv6 only when it is fast enough, otherwise it uses IPv4 instead.
You can ping v6.ipv6-test.com(their IPv6 test server), you may find out it is not very stable.
IPv6 is supported by Chromium all the time, but it has a fallback mechanism.
When certain timeout is reached, Chromium will fallback to use Ipv4.
In brief, Chromium uses IPv6 only when it is fast enough, otherwise it uses IPv4 instead.
You can ping v6.ipv6-test.com(their IPv6 test server), you may find out it is not very stable.