I pretty much had the exact same experience with the unit I'm sending back to them. You can see my graph
here.
Notice that things just got crazy during the cold crash. Temp swings +/1 20F, and gravity swings going right along with them +/1 9 points. The entire time the beer was sitting at 33F +/1 2 degrees, and the gravity never changed from the 1.009.
The developers were great though, insisted on replacing the unit, shipped out a new one right away, and they've been very communicative throughout the process. They told me on Thursday of last week that they were having a meeting that evening, and one of the topics was my wild temp/gravity swings and their correlation.