Well Jeff, in my case the Smart Mode error is not possible since I physically blocked that switch from going into "Smart" mode. I'm thinking that just because the TH "sees" satellites doesn't mean that it has actually received all the GPS data it needs to fly correctly from a new location. But, now that I think about the OP's flights, both take-offs were from the same exact location, so out-of-date GPS date is probably not what caused his erratic flight. Hmm....
I agree that compass calibration (and waiting 10-15 minutes for GPS almanac to update) is only required if the flying location is 100 miles or so from the previous location or it has been several weeks since the last flight.
Interesting, indeed, as to the cause for your darting away, @Rubik.
I don’t recall an earlier discussion... did any telemetry analysis take place to see if any clues were present?