"Home" instance wrong
If I’m not mistaken it will appear in every home instance for character’s that you have. Do you also have an Asura? That’s why the harvesting of it is account bound.
The Quartz should appear in every home instance regardless of whether you have an Asura, Charr, Norn, etc.
As soon as you activate it, it will appear in every home instance. Even if you only have a human character, you can still go to Rata Sum and go there to mine it.
You can only mine it once per day and it doesn’t matter which " home" instance you use. So this is normal behaviour.
You can even mine it in another person’s home instance if you are in a party with them. Still the same node as the one found in your own instances.