Rowan/Will Kenrith "Strategic Planning" Ability bugged [Can't reproduce]

Will Kenrith's 3rd ability says: "Activate Each Blue and Red: The first non-support card in your hand without mana gains half it's mana."

The few times I've activated it and cracked a gem, it doesn't give any mana. However, I just tried putting a support in the top position in my hand and I think it got the mana and nothing else did. In both cases tested this by swapping colors that didn't give a bonus so I could try and discern if the card got half its mana