It's already fixed in the next release. Please check

Στις 13 Νοε 2016 1:45 μ.μ., ο χρήστης "John_of_Reading" <
no-reply@phabricator.wikimedia.org> έγραψε:

John_of_Reading created this task.
John_of_Reading added a project: AutoWikiBrowser.
Herald added a subscriber: Aklapper.
*TASK DESCRIPTION*

Using 5.8.8.0 SVN 12098 at [[Deep diving]], the general fixer wants to
change

<ref name="died" group="nb">

to

<ref name="died group=nb">

*TASK DETAIL*
https://phabricator.wikimedia.org/T150606

*EMAIL PREFERENCES*
https://phabricator.wikimedia.org/settings/panel/emailpreferences/

*To: *John_of_Reading
*Cc: *John_of_Reading, Aklapper, JJMC89, Grind24, Reguyla, Magioladitis,
Dinoguy1000

It's not fixed. Bug confirmed.

I search for this bug yesterday, but did not search again today before filing mine ;)

As inidicated in T150610, this seams to be only in main, I could not reproduce it on user ns or help ns (sandbox)

@Zebulon84 As a workaround chnage

<ref name="foo" group="bar">

to

<ref name="foo" group=bar>