Unwatched specials come and go in Progress Tab from time to time.
I’ve enabled the “include specials” option for the progress tab.
https://i.imgur.com/LaBQnup.jpeg
https://i.imgur.com/KCKDxzK.jpeg
I think there’s just a bug in how some things sync/store. I see this in the Dashboard “Up Next” as well. I know for a fact that I have marked certain shows as completely watched, including specials…but sometimes they “randomly” show back up in those locations. I just chalk it up to loss of data somewhere…maybe Trakt purges data at some point.
Here’s an example i see all the time…in the screenshot, see the “What would you do?” show…the red progress bar is missing episodes from all the way back to 2011. I know for a fact that I have marked those watched before.
It could also be a data migration thing coming from TMDB. Some shows might change their episodes from a normal one to being a Special, and the other way around.