Sherry describes what happens in this edit, https://en.wikipedia.org/w/index.php?title=Homesickness&diff=573215056&oldid=573214608 :
<<[this edit] is the original problem. It gave all of those references the same "name" ("ref name=":4""), which convinced the software using for viewing pages that they were all the same ref.>>
The original reporter, Christopher Thurber, describes the issue, and provides some hints to reproduce:
<<About half of the 18 references I typed into the article on Homesickness disappeared between yesterday and today. I was certain to follow the Save Changes procedure, but many different references reverted to the same single reference. [...] Same bug today. In VE, I placed the cursor in the text, chose "Reference" from the "More" menu, added a reference, (It appeared as it should with the appropriate numerical superscript), Saved the work, returned to check the page...references disappeared from the list. - Window 8, Chrome >>.
<<Hello...I have the same problem [...]. I didn't realized that it happened while I was editing. I only saw it when I saved the article and the number of the references had decreased. This https://en.wikipedia.org/w/index.php?title=Michael_Giannatos&diff=next&oldid=573583391 is the change I was doing when it happened. Could it be related to editing a table with beta? Probably not since I don't see any table on Christopher Thurber's article. After I re-added the references and the new table, every time I click "edit beta" the refs are gone! Before I even do any change! Basically I can't use beta at all on this article! I don't have any issues using the source but, if it's something simple that can be done with beta, I prefer to do it with it. But I can't. Just wanted to say that this is happening to other articles as well. And it's possible to happen and people don't see it. That would be a problem to a long article with lots of references... Mozilla 21, Windows 8.>>
<<[...] every time I am trying to add a reference at a table with VE, it changes it and replaces it with an already existent one. This time I saved the edit just to post it here. https://en.wikipedia.org/w/index.php?title=Dancing_with_the_Stars_%28U.S._season_17%29&diff=prev&oldid=574412488 [...]
Update: Tables were a coincidence. It happened to me again in main article's text. I didn't save the edit this time...>>
I think I saw this renumbering issue at it.wp as well.