I've been waiting for a month to get this unlocked. I finally got it at 20% today, and I have yet to see a single double yield. Out of 47 alchemy reagents, I have not one single time harvested more than one.
Out of dozens of wood and silk nodes, only a few times have I found 4 instead of 3. 4 is not a double yield, by my calculations. What am I doing wrong?