Those are kinda scary velocities - I don't believe them either. I did some calcs using the GPS coords at time 582.501 secs and at time 585.754 secs which yielded a velocity of 10 mph, heading 201°. Seems like another poster speculated the wind was 10 mph, although at a SE heading.
We don't know the scale of the GPS DOP signals except to say they aren't the "standard" scale. But, GPS(0)DOP and GPS(0):hDOP both have relatively low values. (Compared to the first part of this flight and other flights I've seen).The numSats is 16.
So to answer your question I'm leaning towards the GPS coords data are probably OK.. Those velocities do give one pause though.
OK - working directly from the last 5 seconds of GPS coordinates I get basically the same 10.4 mph @ 200°. I think I posted the wind calculation from AirData, which was around 10 mph out of the NNW, but I'm not sure how much we can trust the log data that it was based on, so if it was drifting on a course of 200° that's probably not inconsistent.