I've seen this on the new Express+ I recently activated. My theory is that there isn't space for all the channels I have, so it tries to update, but nothing really happens since there isn't any space left. Hence, the next time you try to update it just repeats the same process. It will automatically download any channel when you launch it, so I've decided to ignore it. You could test my theory by launching one of those channels and then checking for updates and see if the list of 25 changes.
