Steve,
I was thinking the same thing, but I was running in the "above me" mode. Same session I swapped into Hd got what looked like normal readings. Went back to Eco and had a 500ft reading. I Confermed it visually, looked good... bird was starting to ride a thermal. Went from 500ft to 250ft to negitive -400ft, 250ft then 600ft.... ect. The bird never lost any altitude or line of sight. Typically I would see the usual + or - 50ft, but this odd swinging just kind of started out of nowhere.

I use the same boot sequence every time, and the transmitter or pl havent been abused. I do admit I might power up the pl to fast after opening the app, but i have done it that way for 3 or 4 seasons. I just started having issues like a week ago.

I'm starting to think it's linked to either Global warming, Trump,
Or malware from to much internet porn possibly all 3 (not necessarily in that order). One more day of testing and then I will give customer service a call.
Thanks guys,
Ryan S