Well, Open Access does not support the magnification attribute on instances, but not sure if that's your problem or not.
In order to get around this, there's a SKILL function called dbCreateXformPCell() which will take a cellView and create a "viewName_xform" view which does support the magnifcation property (this emulates it by creating a pcell which instantiates the original view, flattens, and then scales).
That is of course assuming that this is actually your problem. It only would be if you're creating instances and expecting the magnification to work on an instance.
In reply to Andrew Beckett: