I got that from watching it live and the day highlights . They showed a small spin in SS6 (maybe spin is the wrong word, more like a half spin and slide wide) and a problem with second gear after that, then a spin again in SS7 and got stuck in reverse up against the bales.

I just watched the WRC+ in-car as well now to check - the one in SS6 is around 4:30, its not much of an impact (not one you would normally expect to break things) but it is enough to stall the car when it hits the berm so its possible the gearbox was weakened then. You don't hear the gear problem until later in the stage.

I can't tell from the in-car if the SS7 spin was stuck in gear or just that he was distracted by the problem and having trouble driving the car without second gear. It obviously wasn't completely broken/stuck because he could select reverse and back up to the bales.

I didn't say it was definitely the spins that damaged the gearbox, just meant that it might have been a factor. I agree that only the team will know what went wrong with it.