You need not pay attention to the opinion of the other mufti. The mufti who ruled – based on the facts presented to him- has issued a ruling based on ijtihad.  Hence if she married another man based on that decision – her marriage is deemed valid.  It does not matter whether the mufti who rendered the decision to that effect made a mistake in his judgment or not since one ijtihad cannot be used to invalidate another one.

 

This was the precedent established by the pious caliphs such as `Umar b. al-Khattab and others.

 

Based on such precedents eminent jurists say: One ijtihad cannot be invoked to break another.

 

Such a rule has greater relevance in matters of marriage and divorce more than any other areas.