No version of Pages for OS X places a .zip extension on Pages documents saved to the local boot drive. If you are adding this extension, stop. The standard extension is .pages, and it is already a zip file that has been renamed with the .pages extension. If you are using Pages v5 thru v5.2.2 on Mavericks, the Pages document is not a zip-compressed, and renamed file, but rather a special Disk folder that only the Apple Finder knows how to make look like a document to Pages.
You cannot change the document format of a Pages document, or any other document by changing, or appending other extensions to it. You must use the File menu : Export To : PDF, Word, etc. Do not append .zip or anything else to the file extension. Word .docx documents are also compressed, zip archives that have been renamed with the .docx extension.
Are you saving to a Dropbox or Microsoft One Drive filesystem? Where are you saving the Pages document too?