Hello!
That's actually a base game feature. My mod does not add anything to do with Batuu, other than a filter to make sure you never receive a text message from one of the NPCs there. The text message you're getting is scripted by Maxis to occur at the start of every new save file and one time in save files that you haven't played since installing the Batuu pack. It's similar to the text message you get from Vlad about the vampire pack.