Could Not Reproduce Lands of one player seem to be shuffled into their library from the battlefield without a reason

[klixnix]

Game ID: 861312468

In a 4 player round of commander at some point between my (klixnix) turn 6 and the beginning of my turn 7, all my lands disappeared from the battlefield without an effect that would cause this that I could identify. My deck size seems to indicate that they were shuffled into my library.

In my 6th turn I cast Villainous Wealth and cast multiple but not all cards from it that were castable. (The window with the castable cards in the exile zone containing Xantcha, Sleeper Agent which I exiled with Villainous Wealth could not be moved anymore and was stuck in place even after I lost the game.)
At the start of my 7th turn I realized that my lands were missing without an effect being played or showing up in the log that should have caused that.

 

[klixnix]

After reviewing the game replay, The lands seem to be shuffled into my library in crimedog's end step after a trigger from Mahadi, Emporium Master. Before that trigger, another trigger from Florian, Voldaren Scion seems to have resolved. These are the only two triggers that were on the stack in that particular end step.