I think it's not a bug, since objects that orbit very close to their home star will experience a mass loss because of the Heavy interference of the Star's gravitation field (a.k.a Tidal Force).
If you are not quite sure about the things that I just said, maybe you could search for a well-known planet called 'WASP-12b'. It is a gas giant that orbit it's own star once in less than 24 hours.
I don't really know if the same thing happens on a terrestrial planet, maybe the solid matter on the planet are heated up too much to a point that they evaporate into gases or even plasma.