Comment by Neywiny
So the way I see it is fundamentally there was an issue with receiving signals on the spacecraft and that caused issues. I'd really like to know more about that. They mention doppler shift but that's bidirectional so even without the spacecraft knowing how fast it's going, they should be able to account for it based on the received signal. Common issues could be reduced receive sensitivity, interference, oscillator drift or instability, or plenty of other things but there's no mention of even one that I've been able to find.
Didn’t they say the initial issue was some compatibility issue with the base station they were working with? Although throughout the article it sounds like they had a ton of software problems and maybe the spacecraft wasn’t quite as baked as they thought at the time of launch.