I guess for the heart-shaped bokeh to be formed in normal direction, the hole should have the heart shape upside down, because according to the principle of pinhole mask, the image of an object though pinhole mask is upside down.
I think this may not happen for light comming far away?
At first it made me think of a fun fact that if you have a chance to view a solar eclipse, you can find a board and make a hole on it. Then you are going to see the light dot behave in wax and wane like a moon durng the whole proces. But later I realized it's light comming from far direction that shows the light source's shape, which is a result of a different theory.