When I clicked the Add button on the default version that popped up it said it was a BluRay.
Clicking the Add button adds from scratch, and sets the media type to the value you've used the last time. Probably you've added a BluRay the last time.
I did not want that so I clicked the button that said Remove From Collection
You just had to set another media type value. If you clicked "remove from owned", it means that you had already clicked the button "add as owned". Instead of removing the video, you could have edited it, to change the media type value.
I then got a pop up stating that I had found a database error and should report it.
Please try.to reproduce this crash again. If you can do it, I'll have a chance to fix the bug.