Form and Field Rule does not work

Form and Field Rule does not work

Dear team,
I am using SD Std Version 9300, trying to use Form and Field Rule but it seem not to work. I try with Category field, uncheck 3 option ( mandate, user can set, user can view). Then on form load I add rule once request create/edit. then it show Category field and allow user to set and mandate field.
But it not working. I try with requester role and create new ticket, but Category field still not show as expected
Do you have any idea
Thank you !
Tai

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