sound like the park lock actuator is sticking.when you press the brake pedal voltage is sent to the park lock actuator to energize and retract to allow you to shift.unless no voltage from stop lamp switch or adjustment issue.i use to have problems with mine when first bought it from truck sitting awhile before bought but has since stopped it.sometime i have to jiggle shifter end button or the shifter itself to get my key out.i am just assuming your design is similiar....but without a look at wiring diagram i dont know.i have all my wiring and diagnostic info which i got from alldatadiy.com.you would have to test circuit when it happens to isolate the problem.