Hi treefingers

Sorry to hear you had some problems.
The two things that I think might possibly have had a bearing are the colour, and the amount of oil used.
I would have been tempted to suggest using about half that amount of Ghee (around 5 grams), as the ideal scenario is to get a concentrated dose into the system.

The other thing that sounds like it might well have played a part is the colour.
It shouldn't have been a 'light green'. Even if you just mix the powdered bud with oil (without cooking) it it should still be fairly dark. Once cooked it's normally a very dark green.
MVP has a good photo of how it should look in his 'Brownies cooked right' thread.

Water bath double broilers are trickier when it comes to keeping the temperature just right (above 80 degrees celsius, but below a 140). I'm wondering if I might have to amend the instructions slightly if others are having a problem with this bit of kit. Let me have a think about that one, and I'll get back to you.