I have a series of sites in a WordPress network where users are invited to subscribe to posts based on a combination of posts for this particular site and to particular categories on each site. Then when an user within the admin publishes a new post those users who have subscribed will get a brief email about it.
My problem came when an Administrator level user was subscribed to sites but wasn't receiving the emails. Yet local testing showed that he should.
Eventually I discovered that when admin users who were Editors or Authors published a post he didn't get an email (yet others did), but when he made a post he did get an email.
It turned out to be the 'pre_user_query' filter 'ure_exclude_administrators' which was modifying the get_users query to exclude Administrators, even though this query had nothing to do with URE.
For the short term we've disabled the plugin so the filter isn't added, but is there any chance the plugin could be edited to only add the filters when it affects URE functions?