What are the consequences for a girl who entered into a state of ihram for Umrah, then menstruated, then returned without completing it due to ignorance, and is her ignorance excused after she performed other Umrahs, got married, and her husband had intercourse with her?

Whoever assumes ihram for Hajj or Umrah must complete it, according to the Almighty's saying: "And complete the Hajj and Umrah for Allah." Renouncing ihram does not lead to any consequence; the one in ihram remains in ihram until they complete their ritual or are released from ihram if they stipulated a condition and the condition was met, or if they were prevented.

The woman mentioned in the question remained in her state of ihram until she returned and completed her ritual, and her marriage is valid. She must offer a fidyah for the destructive prohibitions she committed (such as cutting hair and trimming nails), to resolve the disagreement. The fidyah is by choice: feeding six needy persons, or slaughtering a sheep, or fasting for three days.