Today my Math hat poofed after just 4 to 5 days of having it. It sayid "The math hat of Genius you were using showing signs of age" and then it Poofed. I got it Saturday night (2/4/23).

Leon said his did the same thing...

There appear to be 2 math cap templates.
The brown one is a Unique and follows the rules for Unique respawns and should last a lot longer than 4 to 5 days.
This is currently active in the game.

There is also a green one.
It is not a unique and there are 4 of them currently active.
It lasts 2 weeks.

The Unique cap has marginally better stats but both are awesome.