Build problems & gym entrance

The blueprints bug that plagued me in late March has made a return (see my March 2018 entry for details). Basically, the problem has caused my project to refuse to build a package (as in, create a version that can be run independent of the Unreal editor). I have tried numerous options, with the most drastic being copying all of the assets to a fresh project, and deleting all of the menus. I emailed Epic support again about the issue, and am eager to find out what they suggest. 

All of these options have been time consuming (copying all assets, building a new project, uploading the entire project to Google Drive to send to Epic tech support), and the UE4 engine cannot be used while the tasks are processing. While I was waiting, I started modeling the gym entrance: