iTunes Help. Duplicate Purchased Songs.

Recently I have been having trouble when preordering albums off iTunes.

For example, when I preorder an album, the songs that are available will begin to download. However when more songs become available later, they will download but they will download twice. This happens when only a few songs become available and when the rest of the album is ready. So basically, I have two songs of every album I've purchased in the last 6 months. I've preordered albums in the past and I've never had a problem like this before. I'm currently using 11.3.