If you left Click a woven echo in the faction Vendor and then left click again it charges you for the woven echo but deletes the woven echo. This is a huge problem i just wasted like 3000 currency by mistake and wanted to test it to make sure it was really a bug because I had to make sure it was not just going into my woven echos tab. If you Shift right click it works without issue you get charged for the woven echo and it goes into the woven echoes tab.
What should happen is if you left click then left click again it should return the charge or maybe you need to not actually charge for the echo until the character actually puts the echo in their inventory.