Yes, which is necessary because it’s a link. Links in Roon are the key to bringing other information objects into the mix. Normally the Primary artist link would connect you to metadata about that artist; here it connect you to other albums with that same link.
The Album artist field is textual only - no links. (Although Roon will attempt to find links within it. See here for example). This text is used for sorting, filtering and searching and usually matches whatever description is on the album.
If two albums have the same primary artist then they will appear together as an artist’s work when you click that artist - the album artist is immaterial then.