In French (dunno if it does that in other languages), when you only have one project archived in a category, there’s a spacing issue between the « 1 » and the « archivé ».
It should read « 1 archivé » but it reads « 1archivé », as you can see in the screenshot.
When you archive a second one, it properly shows « 2 archivé(s) » instead. (however the « (s) » is useless as this only shows up for more than 1 archived projects, in which case there’s always the plural « s » at the end).
Cheers!