iTunes Creating New Artist When I Import Content

Every time I add a new album to an already existent artist in my iTunes library, it creates a new artist category (from the same exact name and all of the same Info) and does not group these albums in my already existent artist category. Yes I do know to check the details of these albums to make sure they are all sorted accordingly, and everything matches, but it will not sort them in the existing artist.

This only started after the new version of iTunes came out last fall, and is extremely annoying, especially on my iPod.

Does anyone else have this problem and what should I do?