This was a rumour when AXS first came out and it’s been discussed again at this year’s Tour. Teams are using non-standard chainrings so that that they don’t have to use the 10 tooth. Movistar are using 54/41 rings on flat stages.
Using smaller chainrings put you at a disadvantage across the full range of gears, not just when you’re in the 10 sprocket.
Mike