It appears that if you have more than 8 or so lists some lists are simply not shown in the list selection popup when you want to assign a movie to one or more lists in the web user interface.
This is really an issue for me since I would want to have many more lists than I currently have. I have worked around it by combining several of my lists into single lists but this is far from ideal.
It would be really nice if this could be fixed.
I've tried this on IE, Chrome and Edge and it makes no difference which browser I use.