Welcome to TBN New member
I don't have a Case but I do get a beeping sound if I get off of the seat with the engine running and forget to set the parking brake. If you have a parking brake try setting it before you get out. It also sounds if I try to move the tractor with the brake on which is a good feature. If that's not the source of your buzzer I'm sure there is a way to bypass the seat switch.