It’s not the command sets. Those are fine. That’s why this is so frustrating and why it looks so much like Leviton just broke something.
There is one other possibility that occurs to me, but it’s super technical and unfortunately I haven’t been feeling well I haven’t had time to research it. And why I wish Leviton support was involved. I think there may be a possibility that the state change is being reported in a different Association group than the smartthings hub expects because of some supertechnical changes that occurred with Zwave plus. But I’m not feeling up to researching this right now.
I’m going to tag couple of people who might be interested, but no guarantees that they’ll have time to look into it either.
The main point here is that some people who are buying the newest Leviton zwave plus wall switches and the newest GE zwave plus Wall switches are reporting either significant delays in status changes being updated in the smart things mobile app, or that the status never gets updated at all.
In your case, if you turn on the associated auxiliary switch, the master does turn on the lights, but the SmartThings mobile app does not update. (I’ve forgotten, have you reported it to support? Because that is an officially supported device, so they should look into it as well.)
Other people are reporting that the statuses do update, but can take several minutes to do so.
You could add some polling to solve both of these issues, but as a network engineer, I hate unnecessary polling, so I’m hoping there’s a different solution.
OK, here’s a link to a thread with an example of the GE switch problem. That won’t matter to you, but I’m just including it for research.
And another thread on the Leviton issue:
And now I’m going to tag some individuals. I don’t necessarily expect responses from all of them, but these are the people who may have heard something one way or the other. There have now been at least a half a dozen reports on this issue in the forums, so we know something is going on. 
(And again the Leviton model that you have is on the official compatibility list, but I don’t know if they actually tested it in a three-way set up.)