Tonks goes to see Dumbledore to find out if he knows about the safety of certain members of the Order, and ends up talking about Remus. During HBP, very slightly AU, but only if you wish to see it that way.
Tonks realized how dumb this seemed. She had made Lupin think that someone in the Order had been hurt, and then forced him to make tea for an unwanted visitor who couldn't form a sentence without stuttering or breaking something. Between OoP & HBP. RLNT.