Surrak, Elusive Hunter is not providing the extra mana, as written on the card.
Surrak, Elusive Hunter
Legendary Human Warrior 4/3 creature with Trample
“Can’t have its mana drained or raised.
The first card of the matched color in your hand gains mana equal to the amount of gems of that card’s colors on the board.
At the beginning of your turn: Spell cards in your hand gain 2 mana.
When your opponent casts a Creature card: Draw a card.
This effect can trigger up to 4 time(s) per turn.”
Everything else seems to work except the gaining of mana.