Seat belt/key in ignition chime

[morgal48]

Last week I started hearing the seat belt undone/you left the key in the ignition chiming noise while driving. It will chime twice and stop. I've tried to determine if a particular action on my part is the cause, but it just happens randomly. Any and all help is appreciated. All else seems well with the car, but I fear this is a precursor to some evil occurrence. Only recent changes are DIY transmission, crankcase, and brake fluid service.