Edge 1050 terribly inaccurate gradient readings on 7k day.

just awful gradient readouts today on a 7000ft vert day. Multiple instances of negative gradient when going up on a 10+% road. Page Mill Road in Bay Area. 

Even readouts going down a 20% grade (Redwood Gulch Road) showed a +2%. What is going on? Truly useless and extremely frustrating to be working hard on several 2000ft climbs, only to look down and see 0%, 1%, -3%. 

can someone please help here? I can send the activity if that’s helpful.