This "religious ruling" stuff is less interesting than it sounds. To begin with, while the Islamic Republic of Iran is a totalitarian state, the Twelver Shia hierarchy isn't unified. The supposed ban on nuclear weapons was Khamenei's, and binding only on his followers. But there are several other marja (marjas? marji?), with significant followings even in the security state & IRGC (al-Sistani being a good example).
More importantly, it's pretty clear that the geopolitical rulings are, well, geopolitical in nature. Iran is a nuclear threshold state; its strategy is to come as close to the breakout line as it can and extract concessions for not crossing it. The supposed nuclear fatwa is just public relations strategy. At the point Iran decided the cost/benefit/risk/reward of crossing the threshold made sense, it would be updated.
More importantly, it's pretty clear that the geopolitical rulings are, well, geopolitical in nature. Iran is a nuclear threshold state; its strategy is to come as close to the breakout line as it can and extract concessions for not crossing it. The supposed nuclear fatwa is just public relations strategy. At the point Iran decided the cost/benefit/risk/reward of crossing the threshold made sense, it would be updated.