They're trying not to pay unemployment by saying reduce your hours or we'll fire you after bringing out a policy book they haven't bothered with for the years before. Not a good look for them.

People companies can write whatever they want in a manual or a contract, but if it isn't enforceable under state law, they can wipe their *ss with that paper. You need some input from an employment attorney or 10. My inclination would be to make them fire me, tho.