Since I have a Time Machine drive, I decided to wipe my iMac to test things out. After wiping my iMac's SSD using Recovery Mode's Disk Utility and then reinstalling macOS, I set the computer up as new, and transferred no data. The only setting I changed was enabling right-click on the Magic Mouse. I freshly installed Origin using Safari, and then installed the base game, fresh as well. This didn't fix this issue. It appeared immediately in CAS on the entirely new installation. It's starting to look like the bug is following around my Origin Account, rather than my computers.
And for what it's worth, I'm running the Limited Edition version of the base game. I don't know if the versions of the base game might have different coding, but I just figured I'd just mention it, since it appears to be the only version of the base game (in the U.S. anyway) that didn't get the rebranded, royal blue cover art. At least, in my library, it didn't. The only time I've ever seen it change, is when I set my VPN to Germany, and I get the regional cover art.