You need to always give your Dominican Passport to Customs here. If you come in with a US passport that could be your problem when you leave. Customs here never gets to stamp or scan my US passport.Are you talking here about getting her USA passport unlocked because she’d been in DR over 30 days?
Both Mr AE and I have to do this every time we leave DR, I have to pay, his just gets unlocked because he’s Dominican. Takes two lines sometimes, other times fast and easy.