I have never used myself so I can't say for 100% but if I would guess I would say no there is not
hmm. I currently have 2 permanent invites and one of them is the link that is written on my first and third post. I send a friend the link and she could join from it with no issues. So I don't know why you don't seem to get the "expired" message. And I double checked when I updated the first post to the new link that it was a new code for it so it's not the same code as the one I had up there before.
Got a little sad when I saw the post that the god speed boost would get patched out. If the only problem was the issue at the end where you could get left behind I would make it so when it breaks in two to force it to stop there but as I'm writing this it might look a little silly if it just force stop there.
Anyway I'm going to make runs for the new category in the near future as I got the second place on the old leader bord (going to upload it soon) And if needed to you could always play on an older patch anyway so it's fine imo
I'm also glad you took your time to post here with the information :)