Something has gone crazy in indesign for me. Not sure if its the recent update.
In osx if you open a book and double clikc one of the files, it opens, if you double click it again, it opens another copy, changes made in one reflect in the other. If you make lots of changes to the first document then open it again by accident it overwrites all the changes you made.
I can open many multiples of the same document and its totally confusing me!