Draganfly also offer the foam (soft) rectangular packing that sandwiches between the outside of the frame rail, and the rear of the oil tank (above the oil tank securing bracket).
Suggest you get one, if there is not currently stuck to the outside of the frame rail.
Do not overtighten the toggle bolt which pulls the oil tank up against this packer.
Too much tension (and / or vibration) can cause the brackets welded to the back of the oil tank to crack the tank, and cause leaks which appear to be coming from the banjo nut immediately below.
Difficult to find, cause of persistent leaking. The tank may require removal from the bike to identify the leak; seal the inlet and outlet ports with BSP caps, re-fill with oil and suspend the tank. Eventually the source of the leak will show, and you will be able to see clearly where it is occurring.
Can be resolved with soft solder over the crack.
How do I know this......?
Richard