ANglEAUT: This thread started in the middle of Jan & we are now at the beginning of May. 3 months of intermittent IPv6 issues is too much for me. It's off until I see less complaints.
I think it is important to add the fact it's only really a few people talking about IPv6 issues out of many customers. I, for one, have actually never had a problem with IPv6 and my IPv6 has been solid.
There is however a known problem with one of their BNG's they've done a temporary fix for with a proper fix at a later date once a vendor software update comes out and it has been tested (this has confirmed a fix for this problem looking at the release notes).
If you do have problems then perhaps log a problem record in your Quic account and let them know. There are other factors that have caused problems like for example UniFi UXG firmware breaking it for a while and has only been fixed recently with the latest firmware or Mikrotik RouterOS 7.17+ currently with some rather odd IPv6 bugs - these problems can't be specifically blamed on the ISP because, it isn't the ISP's problem.
I'm an advocate for IPv6 but I'll also freely admit that vendor support sometimes is just terrible.