"...I was temporarily overseas for the time in between..."
CA regards you as a resident until you establish your domicile in the "new" state.
From your description, it sounds like you did not establish your DC domicile until after your trip to Europe.
Therefore it's more accurate to say that you were a tax resident of CA for 7 months and of DC for 5 months, which means that any income you had during that 7 months would be taxable by CA.
For CA's rules on this, see Change of Domicile on page 10 of this CA tax publication:
https://www.ftb.ca.gov/forms/2021/2021-1031-publication.pdf
In TurboTax, you would indicate DC as your State of Residence, and indicate that you also lived in CA during the year.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
