My formula is
The resulting URL (Site URL portion removed) is
Nintex has announced yesterday this functionality is nearing completion and they are aiming for a March release!
That's super exciting!
Annnnd it looks like "Save & Continue" is now released. WOO!
Which version? We are running Forms 2010 v22.214.171.124 and I don't see it.
My guess is that this is only for 2013 / 2016 ..
I don't see it in your release notes: