Similarly, two (unrelated) smart people told me, isn't it cool that we can see the earth's shadow on the moon. There were no eclipses: the moon was just not fu

Similarly, two (unrelated) smart people told me, isn't it cool that we can see the earth's shadow on the moon. There were no eclipses: the moon was just not full. I wonder how they arrived at this conclusion. Is this a strange coincidence or is this a common mistake?