Negated Parts Invisible

[SeeingBlue]

I am a new developer. I started a new project last night. Before I saved and closed, I left a few shapes in the 'Negated' state where they are transparent with a red shade.

Opened Roblox this morning and it wanted to do any update. Afterwards the negated items are not visible, but I can see a wireframe for them. If I select the negated item and try to de-negate it, it gives an error: Unexpected end of file while reading 32 bytes and remains invisible.

I have attached the file that is causing the problem. As a side note before submitting this ticket, I opened the file one last time and noticed one of the negated items returned, but 4 of them are still missing. Mazerunner.zip