Yep, the Palmarian group has some preternatural activity tied to them.
There are witnessed examples of Gregory XVII actually levitating while saying Mass. Some weird stuff.
Bishop Thuc is often maligned for consecrating these clowns, and he should be to some extent, but he did the consecrations before Clemente Dominguez came out as "Pope", due to some apparitions they were having and in which true preternatural phenomena were taking place. He renounced them as soon as he declared himself Pope. Thuc was actually encouraged to ordain/consecrate them at the insistence of a priest who was at the time a professor at Econe. Reportedly this priest initially asked +Lefebvre to do it, and the Archbishop allegedly told them to go visit Thuc. So Thuc didn't do it primarily on his own initiative. It's clear that the poor man was easily influenced, probably having been deeply traumatized by the murder of his family by the Communists ... but that's no evidence that he was insane. I've known a lot of people to do strange/imprudent things from time to time ... without having become insane.
In any case, the Palmarian group holds that the real Paul VI was drugged and held hostage, and they consider him a martyr. Right before Paul VI was allegedly killed, he is said to have bilocated to Clemente Dominguez and appointed him his successor.
Strange stuff indeed.
Dominguez was apparently some insurance salesman who went to the apparition site and then suddenly started having apparitions himself. Some people say he was a notorious public ɧoɱosɛҳųαƖ before all that happened.