Hi Khuffie!
This actually turns out to be a bug in the recent Xcode releases. See my comment here:
The Swift site and bug tracker lists this as a fix that’s been implemented in Xcode 11.5 Beta. The alternatives you have right now are a workaround mentioned in that forum response, or using Xcode 11.5 Beta to ensure didSet gets called.
We are working on adding some author notes for future viewers who may run into this issue until it’s fixed and out in the wild 
Let me know if that helps and thank you for taking the time to follow the course!