Issue is still present in May 2015 Cumulative Update and July 2015 Cumulative Update. Will contact Microsoft on this.
Microsoft has confirmed this issue and will roll out a fix in the next Cumulative Update.
Last week I was notified of an issue where bulk content approval failed for specific users. The list was configured with the default Content Approval.
They would select two or more items to approve and click the “Approve” button in the Ribbon, however that just kept “Working on it”.
Note that single item approval works just fine for them!
When watching with Fiddler and in the ULS logs it was clear that the bulk approval screen threw an Access Denied.
The user was configured with Read permissions on the site and Approve/Contribute permissions on the list (but even with Full Control on the list it failed).
After some playing around with the permission levels and permissions on the web level, it turns out that if the user has “Approve” permission on the site level it works!!
Obviously this may not be possible to grant to your users.
None so far. This was tested on Service Pack 1 (15.0.4605.1000) and September 2014 CU (15.0.4649.1001) individually.
For now either use single item content approval or give the user the “Approve Items” permission on the site level as well (workaround above).