One of the later additions to the game has been the introduction of temporary campaign maps. These maps appear at seemingly random times every now and then, and disappear again as well after usually a few hours. I thought about including them in the campaign spreadsheet, but seeing as I am not convinced they will be reused, I will write here a small article on how I think you should generally approach these and what the potential rewards are (and they are pretty good).
At the time of writing that piece, the feature had not been fully implemented yet, but it has in the mean time, and it is such an addition it merits its own article. So here, I will lay out all the necessary information you need about this feature.