I noticed the voltage, -thought you might have wore it down a bit before the flight. Cold will affect lipos, but all I've noticed so far is shorter flights. One day you'll realize that you don't need a tracker
The same telemetry data that the tracker uses can be captured directly from the audio channel on the vrx, into an android, iphone/ipad, etc. and viewed real time over google maps. Definitely consider going RHCP.