"from 7 February 2022, if sellers upload valid tracking for less than 95% of their trackable orders, their payments will be placed on hold. "

Actually I am a bit befuzzled by the announcement.    If a seller advertises their item as a parcel, why wouldn't they add tracking numbers when posting? 

Maybe it weeds out international sellers who are more likely not to add tracking numbers?

And no I don't have any trouble with syncing - I use Aust Post labels and all my tracking numbers upload automatically - I don't know why they wouldn't.