@Just-Lisa-Now- "I owed in 2018 and used direct debit to pay the balance due and the EIP was direct deposited into that direct debit account."

Does Treasury have that bank account information for some other purpose?  I doubt that the 2018 return was the source.

Here's an interesting (unrelated) case.  Student in 2018, claimed as dependent by parents that year and that was shown on the return, which had a small refund direct deposited.  Has not filed 2019 yet (will no longer be claimed).  Payment was deposited to the account shown on 2018 return.