Saving Custom Stores

I’m not sure if this is a bug or just me goofing up. I have a custom store. For the most part everything works well. I’m able to display stuff on the screen with it, call it’s functions, etc. But when I enable the save function so that it may be called by the ExtractSaveData() function in stores-management (guess on my part, but looks like the right spot), I keep getting an error on line 87.

“(in promise) TypeError: Cannot set properties of undefined (setting ‘buildings’)”

Here’s my save function

state: () => ({
    buildings: new Array<Building>,
save() {
      return {
        buildings: this.buildings,

Any help would be appreciated.
Thanks in advance.

Found the error in the engine. I’ve submitted the Pull Request.