CHARM CHASER WHEN A TALISMAN IS DISCOVERED DURING MINING, THERE IS A 20% CHANCE THAT TWO WILL BE GATHERED.
sorry for the caps, i copied and pasted from the brady guide and i'm too lazy to de-cap it.
i don't think 9 gathers is enough to prove that 20% chance of getting double charms is enough times to say it doesn't work.
also, it sounds like you think you get bonus charms at the end of the quest, and the guide makes is sound like you get the bonus charms as you gather.