They had to change the mast when they changed from a horizontal to a vertical furling-motor setup. The needed to make the slot bigger to fit the motor. My mast also has the reinforcing shell around the lower part of the mast. I was looking at the promo video for the A54 and captured this frame:
Here you can see the original horizontal motor and also the kick-strap in place. It may be because of the change of motor setup they dropped the kicker. I don't think the mizzen has ever had a kicker. Maybe the logic is that if you rig a preventer you can keep the boom down as well. I wonder....
