The children praised her warmly for her good behavior. As a matter of fact, there was no great merit in this, for she could not stand anything stronger than milk; but we are seldom rewarded when by rights we ought to be and sometimes are when we have not deserved it.

这里的大意是动物们都喝醉了，只有一只猫没有，请教各位老师红色字体部分怎么理解？尤其是这个sometimes are,这里是不是省略了什么？