Which plan are you on? When you login to the site and look at the alert does it give you detail? Experian and Equifax provide good detail on accounts in their alers. Transunion is very generic. But once you look at the other two and can match the dollar amounts you know which account caused movement in Transunion.
Here's an example:
FICO® ULTIMATE 3B Member since 2018-12 FICO SCORE 8 Starting scores: 765, 771, 740 Current scores: 827, 819, 826 Goal scores: 830, 830, 830