Can't delete a project just after I imported the files due to still loading

As I just imported a video file (se screenshot for specifications) on my Macbook Pro M1 and I realize the file was wrong I can't delete the project as it shows a progress line whan I return to my Project window (see second screenshot). It takes a long time until it is finished and I can delete the project. I belive this is a new bug as I havent experienced this before.

I am using 
- MacBook Pro (13-inch, M1, 16 GB RAM 2020)

- MacOS Big Sur 11.2.3

Geir