At the moment the problem is not there, but just wanted to mention this as it can be a pesky one.
The error can happen when
has been used in the main controller.
when it's set to false it's not a problem as it won't store the page in the cache.
The problem can be seen when:
- making menu-link to archived articles
- sort + click link + hit backbutton of your browser
Sorting is using GET instead of POST and perhaps it has to with that + also the expiring date (1970) is not good.
so yep you can:
- disable caching, setting to false (main controller)
- change the expire headers when you want to use cache
- or use a back button (image)
when using the backbutton you can make use of
and a thing to keep in mind is that a direct link won't output something. so yep when there is something then output the image and when not then don't display it.