Read delay in App Engine Datastore after put()

I write a code for a blog/news site. Main page has 10 most recent articles and also there is an archive section with all articles sorted by modification time descending. In archive section I use pagination based on cursors and I cache results starting from the second page as pages are changed only when new article is published or existing goes to drafts for some reason. Every page has 10 articles. So when a user hits an archive page with some number (not the first one) memcache is checked for that page number results first. If the page is not there, memcache is checked for the cursor for that page and then results are fetched from datastore using that cursor:

class archivePage:
    def GET(self, page):
        if not page:
            articles = memcache.get('archivePage')
            if not articles:
                articles = fetchArticles()
                memcache.set('archivePage', articles)
        else:
            if int(page) == 0 or int(page) == 1:
                raise web.seeother('/archive')
            articles = memcache.get('archivePage'+page)
            if not articles:
                pageCursor = memcache.get('ArchivePageMapping'+page)
                if not pageCursor:
                    pageMapping = ArchivePageMapping.query(ArchivePageMapping.page == int(page)).get()
                    pageCursor = pageMapping.cursor
                    memcache.set('ArchivePageMapping'+page, pageCursor)
                articles = fetchArticles(cursor=Cursor(urlsafe=pageCursor))
                memcache.set('archivePage'+page, articles)

Every time a new article is created or the status of an existing article is changed (draft/published) I refresh the cache for archive pages results and cursors. I do it after saving an article to the datastore:

class addArticlePage:     
    def POST(self):
        formData = web.input()
        if formData.title and formData.content:
            article = Article(title=for