Insidious Roots reads:

Creature tokens you control have “{T}: Add one mana of any color.”

Whenever one or more creature cards leave your graveyard, create a 0/1 green Plant creature token, then put a +1/+1 counter on each Plant you control.

My opponent in my last round had an entire deck built around spamming surveil to send things to the graveyard to trigger the roots, they were in fact both triggering any time he sent them TO the graveyard, they never once removed anything FROM the graveyard. yet the game was allowing them to usse this bug to spam 8 plant token to take the game.