I have run into a scenario where I am getting an 'Permission Denied' error when attempting to run anything that uses batch, with the sole exception being CRON.

First off, this error is NOT related to the max_allowed_packet issue referred two in every other thread regarding this scenario. First off, my max_allowed_packet is set to 16M, and second, my batch table shows valid requests waiting to be run:

my.cnf:

max_allowed_packet = 16M

drupal.batch table:

15456   ba_Tu-5BZEcFUq3RH37zvx6bvCWJGvlUUtYgADfOlPY 1406048062  ...

The requests being attempted are very small as well, I'm only trying to delete 1 user.

This happens with the primary admin account (UID 1) as well as all other administrators, so it does not appear to be account or access specific.

I am uncertain where to look next for more clues.

MySQL logs do not show any warnings or errors, and the only line in PHP is this:

php drupal: https://www.example.net|1406048063|access denied|X.X.X.X|https://www.example.net/en/batch?op=start&id=15456|https://www.example.net/en/admin/people|1||batch 

IP and Domain censored from above log.

I have also confirmed that there is no '/batch/' folder in my Drupal route that could be messing with the url.