If the missing </ref>-tag is the last ref tag, no error message is displayed.
Works correct: <ref>broken <ref>correct</ref> <references />
Doesn't work : <ref>broken <references />
See also https://bugzilla.wikimedia.org/show_bug.cgi?id=6199#c25 for comments on that
Version: unspecified
Severity: minor
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=26145