Achievement Rewards not claimed

I recently won a game of a world at war map, making it my third. I went to the achievement to claim the reward, and it says 3/6, and the reward was meant to be 8000 gold, but now says 16000, because it's on the next section/level. There's no gold button to claim the reward and my balance is currently just above 10,000, which means I got the reward for coming 1st in the map but not the achievement gold. Anyone else experience this before?