That is a myth. The pay clock does not start until all the doors are closed and the breaks released.
And on long overnight flights the pilot will set the pressure altitude as high as permissible in the cabin to put the passengers to sleep to help out the cabin crew.
Yeah, and that contradiction is in the article too. My experience is that the flight crew gets manic the longer the plane is on the Tarmac. Meanwhile, ground crew is fiddling with some dibbly-bob on the wing, keeping the plane at the gate, and the attendants are ready to explode. But.... They always seem so calm and serene when the plane has to circle, wait in line, or whatever to land. More time in the air? More money? Makes sense.
It could be a myth anyway, but the article seemed to account for your comment about the pay clock — they specifically said they were trying to “make up” for the pay they do NOT get while waiting for the delay.
So I assumed that while they got zero pay during the delay, that their overtime was based on total hours they had to be available, rather than the hours they got paid, so they might get kicked to “overtime pay” if they had already been “on job” more than 8 hours, even if 2 of those hours were unpaid waiting for the plane to depart.
I don’t know if that is the case or not; I’m just noting that the claim was different than the one you refuted.