Playing on the PS5 I've unlocked Tier 1 of SoS Mastery and I've unlocked the first part of Tier 2, The one I'm having issues with is drive the Jubilee 80 miles. I've driven it for over 100 miles and got the trophy but the Mastery section just doesn't update and won't unlock the reward no matter how much I drive it. Anyone else having issues with this? I did ask this on the Technical section a few days ago and no one has got back to me.
I had similar problems with Mastery on the SOS route, but meanwhile I've unlocked Tier 2. I assume that there are still tracking problems. One explanation can be too much traffic on the DTG server. It's best to try it every now and then, it will work again at some point.