I have noticed something rather curious - I have a couple of DVD's on loan (they are not yet overdue although I have moved the due date a couple of times already, if that is relevant).

I moved the "due date" of one of them, then I wanted to check the History for that DVD because I was curious if a loan extension would create a history event (if anyone else is curious, I can tell that it does not). I clicked "ok" in the history window - and suddenly the DVD was overdue; the due date had been moved back to the date when the DVD was initially loaned out.

It is reproducable every time - and does not occur if you press "cancel" instead when closing the History window.

Naturally this is not an earthshattering discovery, it simply struck me as odd.