I assume that by loan out you mean what I would call borrow. Check to see if it is a problem with Kobo by downloading a free ebook in ePUB format. Which Kobo device or app are you using? I don't know what the Overdrive issue is, only know that I have seen something similar with multiple complaints in various forums that seems tied to the Overdrive system of borrowing books from some public libraries.
See this thread on the Adobe forum:
http://forums.adobe.com/message/4474776