Very strange. With an Airspy Mini @ 6MSPS as your metadata shows I’d never expect an image transmission from 1 MHz offset. Assuming you are not in close range of an MW transmitter up or around that frequency mixing up but that would have garbled the modulation too. \
Could have been the ISS somehow but it only just came above your horizon at all half way thru the pass, just when the signal starts coming up. Very odd.