I am using NC 13. I too was having issues where versions didn’t work, and also had the versions link show up twice as others have stated. Here is what I found.
One of the versions links is for the snapshots app, which I had enabled. The other is for the versions app. Turning off the snapshots app not only fixed the versions app, but it also revealed that all the versions I had created while it appeared not to be working were in fact there. In short, it somehow seems that the snapshots app masks my ability to see my file versions which are in fact being properly created, so the versions app was working all along. This is true regardless of which of the two versions links I clicked on.