A customer of ours has reported a "bug" that their live site works differently from the staging environment. What they see is that when a user selects "all" products on a category page, then changes categories, the selection reverts to the default number of items per page items on live but stays at "all" products on staging.
What we found was that the live site had Full Page Cache (FPC) enabled and the staging site had it disabled. Once FPC was enabled on staging server, we were able to replicate the issue in that environment. Checking further, this happens on all of our EE sites and I guess I had never tested/noticed it before.
I understand that FPC is storing a version of the page as generated with the default parameters, but, is there any way to generate the non-cached behavior without using a new URL that includes the show parameter?