I experienced the same thing. Went on a journey a while ago, got the 1 qt warning and added a qt. Then came back and the thing said 1/2 full. Added a 1/2 a quart, then it said too full with the yellow. Drove it like that for a month, then it dropped back down to ok. Went on a second journey, and tracked the car. The thing said 1/2 full along the way. Learned my lesson and didn't add oil. Came back, drove it today, and now it sez full/ok today!
Dumb sensor!