This happens because we send Parsoid something like

<span about="undefined" typeof="mw:Extension/ref" data-mw="..."></span><span about="undefined" typeof="mw:Extension/ref" data-mw="..."></span>

which then gets about-grouped. We need to just drop the about attribute if we don't have it.

Ironically we've had breakage in the other direction before, where Parsoid output multiple adjacent images with about="null". Karma's a bitch :)

Change 76836 had a related patch set uploaded by Catrope:
Remove the DM 'about' attribute from references and reference lists

https://gerrit.wikimedia.org/r/76836

Change 76836 merged by jenkins-bot:
Remove the DM 'about' attribute from references and reference lists

https://gerrit.wikimedia.org/r/76836

Fixed and will get deployed in a little while.

• Bug 52269 has been marked as a duplicate of this bug. ***

Users are reporting that VE is still not saving multiple references:

Reported today by The Devil's Advocate
if I add multiple citations to back a statement, the Visual Editor only saves the first citation I added. This happened once when I added three citations to back a claim and had to add each one individually over the course of three edits and again just now when I had to add a second citation after it didn't get saved. Multiple citations can be added if they are separate as I had added a citation for another statement in the same edit and it was saved.

Reported on the 22nd by Sue Gardner
Last night I created a new article with multiple references, and when I saved the page many of the references disappeared and some I think had jumped around. (I didn't save-as-I-went -- I wrote the whole thing and saved once, at the end.) I can't describe exactly what happened, but here's a diff: [1] the latest revision [2] is roughly what I was aiming to do, and the earlier revision [3] is what I actually achieved. (Ignore the missing reflist: I just hadn't gotten around to figuring out how to add it in VE yet, so I did it afterwards in wiki syntax.)

So, in my initial VE save, it looks like references #5, 6 & 7 disappeared as did #14 and 15. (Numbers taken from the latest revision.) This suggests to me there's a problem with VE saving multiple adjacent references -- when there are multiples adjacent, it seems to save only the first. I think also some references jumped around, but I'm not 100% sure about that.

[1] https://en.wikipedia.org/w/index.php?title=Mansplaining&diff=569638597&oldid=569526861
[2] https://en.wikipedia.org/w/index.php?title=Mansplaining&oldid=569638597
[3] https://en.wikipedia.org/w/index.php?title=Mansplaining&oldid=569526861

(In reply to comment #6)

Users are reporting that VE is still not saving multiple references:

Unfortunately, this is "again", not "still", and is caused by bug 53434 in Parsoid, I think. :-( Marking this as "fixed" but highlighting on that one how urgent this is. Sorry for the disruption.