Redmine

I think this problem only affects the atom of issues list.
There are updated tags created by issue.event_datetime.
But issue.event_datetime is created_on.
I think you need to use updated_on for the atom of issue list.

I re-create the patches for this issue.
In the first pattern, issue_controller overwrites issue.event_datetime between atom exports.
The second pattern, application_controller.rb and common/feed.atom.builder, adds the code for the problem list atom.

Both work, but I don't think it's clean code.
I'll attach both patches in the hope that it will help you think about better code.