Question of distance of the obstacle. Assume the moon is roughly 45° above the horizon. If you are near your garden hedge, you can see the moon over the hedge, but in the puddle at your feet all you will see is the hedge. Move back 12 feet (twice your height), in the puddle which is half-way between you and the hedge you'll see half the moon. For something which is D=1km away, and an individual who is h=1.8m tall, the difference of angle is:
Δθ=atan(2*h/D)=atan(.00360)=0.21°
Compare to the moon's angle with is roughly .5° (in the art, it appears much bigger than this... but then it could be a picture assuming a telescope). So assuming the closer rocks in the back are 1km away (which I find awfully close, especially with the telescope hypothesis), the moon would disappear in the reflection only if its top third was showing. And if these rocks in the back are that close, then the reflection of the mountains behind them wouldn't be so symmetrical either. And if the reflection of the moon isn't showing, it's because the part of the water that could reflect the moon is in the shadow of the rocks, but the drawing doesn't show any shadow on the water...
To get an idea of how big the moon really is:
https://petapixel.com/2013/08/22/this-e ... t-shopped/