Have fibre internet, and connections to some hosts don't work if IPv6 is enabled on my device. That's not great. The host (packagist.org) passes the ipv6-test.com suite (http://ipv6-test.com/validate.php), however the connection test suite (http://ipv6-test.com) fails about 4/5 times (but occasionally succeeds). This points to an issue on Telus' end.
Happy to provide any more diagnostic info as needed, but given that these devices ship with IPv6 enabled by default, I'd imagine this isn't the only thing broken?