All my flights this year JFK-BOG have been aircraft with First Class (not D1) but none have processed upgrades. I’ve stopped asking in the lounge as the response has always been “no comp upgrades on international routes” (which we all know is untrue). C+ has always cleared to a nearly empty cabin.
I think this is just a system error with flights having been previously coded as D1 flights. Very frustrating to say the least.