I know the cause and the temporary solution, but I will report it.
After the update, if any slug in the category is empty, it seems that somehow the encoded string is automatically assigned.
This seems to be happening in a non-English environment. I was in a Japanese environment.
Any slugs will remain empty in the newly created category and there seems to be no problem
For reference, you can go to the edit screen by accessing this as a temporary solution.
Change the value of the number in the category accordingly.
I’m not sure if this is just my problem or a common bug, but I hope it helps.