Can Allah's devising lead to the transformation of a devout believer into an infidel or an atheist, and when does that occur?

A bad ending and the snatching away of faith occur due to a hidden flaw in one's deeds, a bad inner disposition, and an evil hidden within the self. This is part of Allah's cunning (makr) towards His servant, as a recompense for him. Whoever obeys Allah and remains steadfast in His command, outwardly and inwardly, Allah will grant him success and facilitate ease for him. Among the punishments for sins and transgressions are: Allah's cunning against the cunning, the deviation of the deviant heart, and the overturning of the heart until it sees falsehood as truth and truth as falsehood. It is not permissible for Allah to punish His saints and admit them into Hell, and to bless His enemies and admit them into Paradise; for that would contradict His wisdom and justice. Most people harbor wrong assumptions about Allah, evil assumptions concerning themselves and what He does to others. None are safe from this except those who know Allah, His names and attributes, and who comprehend the implications of His praise and wisdom.