Well, there had to be some cause for the sudden turnaround and discrepancies.

My favourite used to be the simplest one: a mind transfer experiment gone wrong — whether by accident (as in "The Fly"), outside interference (or trap?), or maybe Lucrezia outsmarted herself or reached too far beyond her firm grasp (like if she tried to transfer herself into that "Muse of Time"). Considering she already had interest in this area.

But such great increase in scope also increases likelihood of other actors participating. This alone makes (B) and (C2) almost as plausible as the simplest version.