Opening a document with Section Access and data reduction enabled in QlikView Desktop will always try to reduce the data based on your account. You will end up with a limited set of data and this will be the content of the document after you save it. Opening it again as a different user for example will often break things because a lot of data is missing.
However, opening a document and performing a Reload will undo the reduction and expand the data back to the full set. Saving this document will produce a fully loaded document that can be opened by anyone with permission.
Saving a document while data reduction is in effect is not a good idea. If you have a server, make sure the document is reloaded after any change you make to the original.