MikeCL and there hasn't been an official Godot forum until the foundation created the current one
There used to be a forum on godotengine.org way back when it first open sourced. The site was hosted by the software freedom conservancy (IIRC) back then and their infrastructure couldn't really cope with it, so after a while the forum there got closed down.
Now I don't exactly recall if the case was that the original forums DB just couldn't successfully be imported over to the new forum software or what but I think I recall the admin previous to me back in the day mentioning that the forum here did have it's roots with the OG tho. So this one is, at least partially & in spirit - the continuation of the OG forum, but with a database loss at some point such that posts from godot v1.x era were lost...
And the new forum on godotengine.org is more so the replacement of the Stack Exchange-esque Q&A system that they were hosting for a while there(which had it's own share of problems).
At least that's the gist of it.
Credit where it's due, there was also one @BinaryOrange as the host and primary admin at one point, chronologically I think between me and @TwistedTwigleg IIRC.