There are multiple users whose names start with '''Adrian '''. Searching for Adrian_, Adrian+, or Adrian%20 produces no results.
compare:
http://en.wikipedia.org/w/api.php?action=query&list=allusers&aulimit=1&auprop=groups|editcount&auprefix=Adrian
http://en.wikipedia.org/w/api.php?action=query&list=allusers&aulimit=1&auprop=groups|editcount&auprefix=Adrian%20
The result of the second query should be the query-continue value returned from the first. (at least at the moment. not sure if anything has precedence over a space)
Version: 1.11.x
Severity: normal
URL: http://en.wikipedia.org/w/api.php?action=query&list=allusers&aulimit=1&auprop=groups|editcount&auprefix=Adrian%20