Also watch the extras of the same vid. If you're making perfect rifflle shuffle every time, the process gets cyclic and the first cards order is repeated the eighth time.

Yup, I've read that too! It is mostly theoretical tho, and I wager that it would very very rarely happen in real life. One unpremeditated perfect riffle shuffle is uncommon enough, so getting eight in a row would be close to impossible.  Still, it's a fun tidbit to know. ^-^

 

Also, the 8 perfect riffle shuffle rule is applicable to 52-card bridge decks. I wonder if it's the same for the Tarot.

The period might be different because 78 is not 52.

Now watch this guy make five perfect shuffles, in a row!

I still think it's very highly improbable to execute a perfect riffle shuffle unintentionally, but wow that's some mad skillz! :o

 

But I guess one must consider sometimes using assymetric piles to be absolutely sure. Maybe one has some latent cardist skills one's not aware off. ;)