A few days ago I had a book I sent marked received and the recipient not only sent me a friendly PM thanking me for it, she specifically mentioned the book by name and why she had ordered it.

Today I got the book returned to me for insufficient postage - it never even reached her.

Huh?

That IS odd...I wonder if maybe she ordered two copies of the book and got confused on which was which?  Or...maybe she requested it from someone else, the request timed out so it rolled to you, but the first sender sent it anyway?  So, she got the other copy of the book but you are the only one showing on her account page so she assumed it was you that sent it.

Either way, that's a weird one!

I've read a few posts in the CMT forum where people were going out of town/ would be out for surgery, and were marking books received before they actually arrived so that the sender would get the credits.  Maybe that's what happened.

I'd guess the member had someone else send it and forget to mark it mailed, so you got the order too. I've had one marked received with a detailed PM less than 3 hours after I dropped it the PO. 

Whoa, that's weird.  Did you PM her about the returned book?

Yeah I did PM her. Waiting to see what she says.

Normally, I would have figured she had simply gotten another copy from someone else who had forgotten to mark it mailed and the request had rolled over to me. But my copy of the book was the only one in the system - in fact this person ordered it after the only wisher on it had turned it down!

Ah, well, I just got some books in the mail today I'd bought on e-bay...and realized I'd accidentally already left feedback because the lot was similar to another one I'd gotten earlier.

Well it turns out she had accidentally marked my book received when she had actually received another book with a similar title and subject. So that little mystery is all cleared up!