There is a known bug with Curie, when dismissed as a companion, would not go to any settlement, but return to the Clinic at Vault 81 instead.

This bug activates if during running the Hole In The Wall quest the player doesn't immediately take Curie on as a companion as soon as the pop-up notifiation "Curie is now available as companion" appears, but talks to Austin instead as the quest objective marker suggests.

I found a fix provided by Alien at the Steam community forums and thought it might come useful for some players here on Nexus.

Converted his recommendations into a simple batch .txt file. Please find instructions on installation and use in the included readme file.

Have fun!