Well, THAT’S really disappointing. They claimed to have fixed this on the Avid site. Then someone using Cubase said they didn’t fix anything. They’ve set it up to work with S1, so if you try using it with Artist Control, you actually lose features that HAD worked with the PT App. I’m talking really basic stuff like BANKING! 
Avid says they’ll fix this by 1st quarter 2020. We’ll see.
Anyway, now you’re saying that it’s great. I’m really glad they fixed the crashing issue. But even that is suspect since you were on an all Mac system. All of the PC people have never been able to get that tracks page to work without crashing! 
So I don’t really know what to think.
I’ve downloaded 19.12 onto my iPad. But I’ve been waiting to update my Artist Series hardware to 19.12 because it’s SO STABLE ON 18.3. I’m not sure how much use I’ll actually get out of it without the S1 hardware. What I do know, is that, without that Mixing Mirroring issue being resolved, I’m way more inclined to wait before firing mine up. 