Does thinking about one's wife, which led to ejaculation after the first stage of exiting the state of ihram (al-tahallul al-asghar) and before the Ifadah circumambulation, invalidate the Hajj, and what are the consequences?

The Hajj is not invalidated by seminal emission (inzal) resulting merely from thought, and no expiatory offering (fidyah) is required according to the majority of scholars (Hanafis, Shafi'is, and Hanbalis), and this is the most preponderant opinion. As for the Malikis, they hold that Hajj is invalidated if seminal emission occurs due to sustained looking or thought before throwing the Jamrat al-Aqabah, and a sacrificial offering (hady) becomes obligatory if it results merely from thought or looking. However, after throwing the Jamrah, Hajj is not invalidated, but a fidyah becomes obligatory.