Nature’s Rhythm doesn’t give mana to power 4+ creatures
This is not fixed by the Patch Notes 7.2.0.104542 update!
I have had it trigger, but usually it doesn’t eg waverider which is power 4.
I think only give mana to the creature you fetch when you have at least one creature in play. So seems to try to reinforce creatures and if you have none of them also don´t give mana to your creature. @Magic_PQ_Support_Team
We have passed this issue for investigation by the QA Team.