Changes made to a sublevel in a persistent level do not transfer to the primary sublevel .umap

Changes made to a sublevel in a persistent level do not transfer to the primary sublevel .umap, however changes made to the .umap appear when it is loaded as a sublevel.

Regression (yes) issue (does not) occur in 4.12.5

1. Download, unzip, open attached project
2. Open Main.umap
3. Load Map_Basic as a sublevel
4. Make any change to the sublevel and save it
5. File>Open Level>Map_Basic

Results

Changes made to sublevel are not saved in the .umap file

Expected

Changes made to the sublevel as a sublevel are saved and appear when the .umap file is opened.