I have seen this addressed before. I have this issue as well. I was asking to see if anyone has found a fix for it without reloading a prior save, or if we can expect a MOD/Patch for it? I am on PS4, so mods may be awhile down the road. I have maxed her out and can get her to follow me as a companion. It is just when I dismiss her, she ALWAYS runs back to Vault 81 and stands outside the Science Room. I do believe I have seen this reported as well with many other people. First off, all settlements I try to send her to are not full, and even sending her to an empty one doesn't work. I try to hurry and assign her a task before she gets away, that doesn't work either. I do believe it is related to how a player completes the mission "Hole In The Wall" on to if the selected player gets the glitch or not. Wiki states:

• Upon dismissal Curie will reappear outside the medical room in Vault 81, regardless of where she is dismissed, even if dismissed to Sanctuary while in Sanctuary, she will immediately sprint toward Vault 81. ^[verified] To fix this, reload an earlier save file and don't give the cure to Dr. Forsythe at the end of the "Hole in the Wall" quest until AFTER speaking to Curie inside the doctor's clinic, she won't actually enter the room herself so you have to get behind Curie and push her into the clinic, she will then initiate the proper dialogue to become a companion and will stay at the players chosen settlement. Alternatively, "resetquest comcurie" and then "setstage comcurie 83" will trigger the join companion dialogue, after which Curie can be moved as required.

So hopefully someone knows a way around it without having to reload a prior save. I was around level 20 when I did this, I am 157 now. Hopefully, if no one knows another fix, they will patch it soon. Too bad, console command would fix it! PS4 though!