Memory leak when importing assets

When importing assets, memory usage climbs but is never freed.

1. Create new project, any type
2. Download Attached zip and unzip folder
3. Open Task Manager and look for UE4Editor.exe, note memory usage
4. Import all assets in unzipped folder
5. Watch UE4Editor.exe in Tasks Manager

RESULT:

Memory usage continues to climb as assets are imported and it is never freed.

EXPECTED:

Memory is freed after assets are imported and saved.

ThumbnailTools::GenerateThumbnailForObjectToSaveToDisk memory leak?