2019-07-12 : If Rienne dies at the same time as one or more other multicolored creatures you control, its last ability triggers for each of those creatures.

2019-07-12 : If Rienne leaves the battlefield after its ability has triggered but before the next end step, its delayed triggered ability will still return the card.

2019-07-12 : If a multicolored creature you control leaves the graveyard after it dies but before the delayed triggered ability resolves, it will not return to its owner's hand.

2019-07-12 : If an effect causes a non-multicolored creature to become multicolored and that creature dies, the non-multicolored card will return to its owner's hand.