What if Bogo set Judy on traffic duty not because she is a bunny but because he set any new recruit on traffic duty. And he tells Judy its because she is a bunny or not good enough to be a real cop to test how she might react to that. Like some sort of test of character of his own.
And as Nick is assigned to Bogos troop, he sent Nick to traffic duty as well but Judy then insists do go on traffic duty with him because she wants him to be her partner no matter the job they might get assigned to even though she already had proven herself to Bogo.
Just my little idea ^^