Playing on iOS, latest update.
When playing Warrior, I used Stolen Goods to pull C’Thun from my deck. However, despite C’Thun receiving the buff, the Eyestalk did not.
I should mention that C’Thun is not normally a Taunt minion, but is given Taunt by Twilight Geomancer in this instance.
So just to recreate the steps:
- Played Twilight Geomancer to give C’Thun the buff and Taunt keyword.
- Have Eyestalk of C’Thun in hand.
- play Stolen Goods to draw C’Thun - it receives buff and the Eyestalk does not.
Update: This also seems to be the case with Grimy Gadgeteer. (The Warrior card that buffs a random minion in hand at end of turn.) When Grimy Gadgeteer buffs C’Thun at end of turn, the Eyestalk is also not buffed.