I use OO in German. 
It's version OOO300m15 (Build: 9379)
(despite the information given in the issues header;
sorry, didn't know how to enter correct version code!)

Having opened an existing odt-file read only (file system attribute), we might
decide to change the working mode to alterable (click to "Datei bearbeiten").
We are asked, if we want to work on a copy. If we agree, a copy is generated and
opened for r/w (all OK).

But it seems as if it was opened as a totally new instance. All information on
the position I was navigating to, on the viewing mode, the zoom factor, etc. are
lost! Hard to understand, if we consider the action to be simply a change on the
working mode. I would expect the writer to re-position to my latest position and
to set all the viewing options I already entered.