On a site that was recently upgraded from v8.0 Update 3 to v8.1 Update 3, editors are reporting that when they attempt to change the template of an item, they end up on the login page. These users are all members of the
sitecore\Sitecore Client Maintaining group and should have access to this functionality. When they click the button in the ribbon, the following appears in the logs:
WARN Request is redirected to login page. Requested url: /sitecore/shell/Applications/Templates/Change template.aspx?id=%7B05F2603F-DF10-42E8-B9E2-4A25DECFDFF1%7D, User: sitecore\editorUserId, Website: shell
There have been several other cases where the security settings in core have impacted the editors, but I can't find what is causing this one.