It looks like you have to remove a spacer similar to part #4 in the Suntour Cyclone exploded diagram posted on this thread shows.
The derailleur upper body at the upper pivot should mount up very close against the dropout with just enough space to still let it freely swing back as most, if not all derailleurs i have used/encountered do, as the placement of your derailleur stop screw seem to also confirm.

Chombi