When foo enters the battlefield, return bar to your hand

Some time ago I saw a problem where the AI played a land that enforces to return a land to AI's hand. As this land was the only available land, the AI produced an endless loop. I cannot recall which land this was and I think that this was fixed (not sure about this, though).
Now I see the same problem with Whitemane Lion: when it enters the battlefield, return a creature (which is Whitemane Lion as it is the only creature)...
Now I see the same problem with Whitemane Lion: when it enters the battlefield, return a creature (which is Whitemane Lion as it is the only creature)...