I frequently have this same issue. Multiple tabs will display as a certain file opened. The only fix I have found is entirely quitting Illustrator and re-opening, which is very frustrating when I am working with many files, especially if I am mid-way through editing them.
Sometimes Illustrator does this when I first open the files, but sometimes does this after I have had some files open for awhile, and try to open another file.
I frequently have this same issue. Multiple tabs will display as a certain file opened. The only fix I have found is entirely quitting Illustrator and re-opening, which is very frustrating when I am working with many files, especially if I am mid-way through editing them.
Sometimes Illustrator does this when I first open the files, but sometimes does this after I have had some files open for awhile, and try to open another file.