Munoz had overstayed her visa

Even B.T. this would have been a problem.

If you have been married to the U.S. citizen petitioner for less than two years at the time your Form I-485 is approved, USCIS will grant you lawful permanent resident status for two years on a conditional basis under INA 216.

Long story short, there is a process for this, and you have to keep up with it.
Marrying a US citizen DOES NOT result in an automatic pathway to citizenship.

///This was news to me. I thought citizenship for spouses was automatic.