Something strange or magical happened to Wang Wei during his Lust Trial in the Pagoda. There were two completely different women that appeared in his trial, which was supposedly impossible.
Afterward, he asked the people who created the Pagoda, and they told him that this was not supposed to happen. An inquiry was made to find the cause of this anomaly, but nothing was ever discovered.
The best explanation was either that the Pagoda malfunctioned or someone tampered with it. However, neither of these explanations actually made sense. As a Quasi-Emperor Origin Artifact, it is impossible for the Pagoda to malfunction on its own.
As for being tempered with, how powerful would somebody have to be able to do such a thing without alerting all the powerful people in the sect? After breaking through the Supernatural Realm, Wang Wei was privy to a few secrets of the sect. As such, he knew how truly powerful it actually was.