This has been fixed (again) in Patch 1.19.31
Existing clowns will not be deleted.
Check on their names and delete them through your household manager.
I have the same issue and it's super annoying! I actually put a couple of closets in one of the restaurants and when one of the of-duty clowns turned up tried to fix it. But all her hair was different for each clothing category, and none were clown style. Even so I changed her hair & clothing for the formal category and when she came out of the closet her hair was still clown style.
I didn't think I had any screenshots, but then I found this (she's outside the window).
I think I am going to delete her and see how that works. It's just such an ugly mess when everything and every Sim around is so bright and cheerful.
It looks like there's an outfit called 'situation'.
This is the outfit all the clown hair gets generated.
I wonder if they forgot to disable it for this.
