Does a person remain in a state of ihram after their ihram for Hajj becomes invalidated due to intentional emission of semen, and are all their subsequent civil and religious actions nullified?

First: Masturbation is forbidden, whether during Hajj or otherwise, and it is more severely prohibited during ihram. However, according to the majority of jurists, it does not invalidate Hajj, while the Maliki school holds that it does. According to the majority, a sacrifice (a camel according to the Hanbalis) is required. As for those who believe it invalidates Hajj, the pilgrim must complete it and perform it again the following year. The preponderant opinion is that Hajj is not invalidated, due to lack of evidence and the weakness of analogy with sexual intercourse.

Second: Not completing Hajj is a major error, for an invalidated Hajj must be completed. If the pilgrim in ihram does not complete it, he remains in his state of ihram.

Third: Based on the opinion of the majority of jurists, your Hajj was not invalidated by masturbation and should have been completed. If you did not complete the Tawaf al-Ifadah or the Sa'y of Hajj, you remain in your state of ihram, and performing 'Umrah does not release you. You must go to Makkah and perform the Tawaf and Sa'y to be released from your Hajj. If you performed the Rami (stoning of the pillars) without intention, a sacrifice is required. Marriage contracts entered into while in ihram are void and must be re-contracted after release. What you committed of the prohibitions of ihram is excused due to ignorance.

Fourth: The condition (of being prevented from completing the rites) made at the time of ihram does not apply if you were not firm in it, and it is of no benefit here as there was no impediment preventing you from completing the rituals. You must repent to Allah for your negligence in seeking knowledge and learning the matters of your worship.