IPv6 MTU issues again?

[badmtu]

Some sites have been loading very poorly if I leave IPv6 enabled in Firefox.

Netflix is the main example. Takes minutes to load the page, usually stalling on a TLS connection to assets.nflxext.com

If I disable IPv6 in about:config, it loads instantly. This happened like a year ago due to some MTU issue and was resolved with some changes on Sonic's side.

Another example site:
slot1-images.wikia.nocookie.net which is loaded when visiting this page for example: https://hyperioncantos.fandom.com/wiki/Meina_Gladstone

For whatever reason, Chrome doesn't seem to be as affected.

[badmtu]

Still experiencing this issue. I forgot to mention this is on Fusion X2. It's frustrating having to disable IPv6 every time I want to watch Netflix.

Here is the thread I referenced.
viewtopic.php?f=10&t=8264

The symptoms are quite similar although I'm not sure if it's cloudflare again this time.