As DSv8 was trained on 1:1, it wants to add moons, if it has to add space to the right and left. Don't just prompt "moon", but defining it like "a single massive crescent moon" and locating it like "a single glowing moon in the upper left corner of the night sky". Use negative prompt: "two moons, multiple moons, dual moons, double moons, twin moons, second moon, duplicate clones, split screen"
A watercolor. A fantasy Victorian neighborhood with cottages with detailed gingerbread trimming. A cottage garden surrounds the cottage. A white picket fence is in the front.