Duplicate pages appearing

Help! I have duplicate pages appearing in a new (live) site.

The site has been working fine for a couple of weeks (it went live at the start of October), but now duplicate pages have started appearing, and, since they are taking precedence over the original pages, the site is showing their content (which is blank) instead.

It seems to be related to the pagePath data in the perch2_pages DB table. The duplicate pages are showing the domain name as part of the pagePath, whereas the original pages show relative paths. See screenshot here: https://jonathanbrain.com/files/oddball_db.png

I'd appreciate it if you could help me resolve this urgently!

Here are the diagnostics:

    Perch: 2.8.13
    Production mode: Production (100)
    Installed apps: content (2.8.13), assets (2.8.13), categories (2.8.13), perch_blog (4.6), perch_forms (1.8.3)
    DB driver: PDO
    DB tables: perch2_blog_authors, perch2_blog_comments, perch2_blog_index, perch2_blog_posts, perch2_blog_posts_to_tags, perch2_blog_sections, perch2_blog_tags, perch2_categories, perch2_category_counts, perch2_category_sets, perch2_content_index, perch2_content_items, perch2_content_regions, perch2_forms, perch2_forms_responses, perch2_navigation, perch2_navigation_pages, perch2_page_templates, perch2_pages, perch2_resource_log, perch2_resource_tags, perch2_resources, perch2_resources_to_tags, perch2_settings, perch2_user_privileges, perch2_user_role_privileges, perch2_user_roles, perch2_users
    Users: 2
    App runtimes:

    <?php
        $apps_list = array(
            'content', 
            'categories',
            'perch_blog',
            'perch_forms'
        );

    Scheduled tasks for perch_blog: delete_spam_comments (1440 mins)
    Editor plug-ins: markitup
    H1: 3ddace779a85fc0bfc002f2fdffc4199
    L1: 360bea033afdf056c9f38574ebfbce90
    headerColour: #ffffff
    content_singlePageEdit: 1
    helpURL:
    siteURL: /
    hideBranding: 0
    content_collapseList: 1
    lang: en-gb
    update_2.8.13: done
    latest_version: 2.8.8
    on_sale_version: 2.8.13
    perch_blog_update: 5.0
    perch_blog_post_url: /news-blog/{postSlug}
    headerScheme: light
    perch_blog_slug_format: {postID}-{postTitle}
    perch_blog_akismet_key:
    perch_blog_max_spam_days: 0
    dashboard: 0
    hide_pwd_reset: 0
    content_hideNonEditableRegions: 0
    content_frontend_edit: 0
    perch_blog_comment_notify: 0
    PERCH_DEVELOPMENT: 10
    PERCH_STAGING: 50
    PERCH_PRODUCTION: 100
    PERCH_DB_USERNAME: oddball
    PERCH_DB_SERVER: mysql9.namesco.net
    PERCH_DB_DATABASE: VF10209_oddball
    PERCH_DB_PREFIX: perch2_
    PERCH_TZ: UTC
    PERCH_EMAIL_FROM: jon@jonathanbrain.com
    PERCH_EMAIL_FROM_NAME: Jon Brain
    PERCH_LOGINPATH: /perch
    PERCH_PATH: /var/www/web/perch
    PERCH_CORE: /var/www/web/perch/core
    PERCH_RESFILEPATH: /var/www/web/perch/resources
    PERCH_RESPATH: /perch/resources
    PERCH_HTML5: 1
    PERCH_RUNWAY:
    PERCH_ERROR_MODE: DIE
    PERCH_DATE_LONG: %d %B %Y
    PERCH_DATE_SHORT: %d %b %Y
    PERCH_TIME_SHORT: %H:%M
    PERCH_TIME_LONG: %H:%M:%S
    PERCH_DEBUG:
    PERCH_PREVIEW_ARG: preview
    PERCH_TEMPLATE_PATH: /var/www/web/perch/templates
    PERCH_DEFAULT_DOC: index.php
    PERCH_DEFAULT_EXT: .php
    PERCH_PRODUCTION_MODE: 100
    PERCH_RWD:
    PERCH_HTML_ENTITIES:
    PERCH_SSL:
    PERCH_STRIPSLASHES:
    PERCH_PROGRESSIVE_FLUSH: 1
    PERCH_AUTH_PLUGIN:
    PERCH_DB_CHARSET: utf8
    PERCH_DB_PORT:
    PERCH_DB_SOCKET:
    PERCH_SESSION_TIMEOUT_MINS: 20

Hosting settings

    PHP: 5.6.14
    Zend: 2.6.0
    OS: Linux
    SAPI: cgi-fcgi
    Safe mode: not detected
    MySQL client: mysqlnd 5.0.11-dev - 20120503 - $Id: 3c688b6bbc30d36af3ac34fdd4b7b5b787fe5555 $
    MySQL server: 5.5.45-log
    Extensions: Core, date, ereg, libxml, openssl, pcre, sqlite3, zlib, bcmath, bz2, calendar, ctype, curl, dba, dom, enchant, hash, fileinfo, filter, ftp, gd, gettext, gmp, SPL, iconv, session, intl, json, ldap, mbstring, mcrypt, mssql, standard, mysqlnd, mysqli, odbc, pcntl, mysql, PDO, pdo_dblib, pdo_mysql, PDO_ODBC, pdo_pgsql, pdo_sqlite, pgsql, Phar, posix, pspell, readline, recode, Reflection, imap, shmop, SimpleXML, snmp, soap, sockets, exif, sysvmsg, sysvsem, sysvshm, tidy, tokenizer, wddx, xml, xmlreader, xmlrpc, xmlwriter, xsl, zip, cgi-fcgi, mhash, ionCube Loader
    GD: Yes
    ImageMagick: No
    PHP max upload size: 128M
    PHP max form post size: 128M
    PHP memory limit: 128M
    Total max uploadable file size: 128M
    Resource folder writeable: Yes
    Session timeout: 24 minutes
    Native JSON: Yes
    Filter functions: Yes
    Transliteration functions: Yes
    PATH: /sbin:/usr/sbin:/bin:/usr/bin
    DOCUMENT_ROOT: /var/www/web
    ORIG_SCRIPT_NAME: /.platform.cgi-bin/php56-cgi
    ORIG_PATH_TRANSLATED: /var/www/web/perch/core/settings/diagnostics/index.php
    ORIG_PATH_INFO: /perch/core/settings/diagnostics/index.php
    ORIG_SCRIPT_FILENAME: /usr/share/web/cgi-bin/php56-cgi
    HTTP_CONNECTION: close
    SCRIPT_NAME: https://www.oddball.co.uk/perch/core/settings/diagnostics/?extended
    REQUEST_URI: /perch/core/settings/diagnostics/?extended
    QUERY_STRING: extended
    REQUEST_METHOD: GET
    SERVER_PROTOCOL: HTTP/1.1
    GATEWAY_INTERFACE: CGI/1.1
    REDIRECT_URL: https://www.oddball.co.uk/perch/core/settings/diagnostics/?extended
    REDIRECT_QUERY_STRING: extended
    REMOTE_PORT: 27303
    SCRIPT_FILENAME: /var/www/web/perch/core/settings/diagnostics/index.php
    SERVER_ADMIN: webmaster@this.domain
    CONTEXT_DOCUMENT_ROOT: /usr/share/web/cgi-bin
    CONTEXT_PREFIX: /.platform.cgi-bin
    REQUEST_SCHEME: http
    REMOTE_ADDR: 80.7.85.2
    SERVER_PORT: 80
    SERVER_ADDR: 192.168.0.81
    SERVER_NAME: www.oddball.co.uk
    SERVER_SOFTWARE: Apache
    HTTP_COOKIE: cmsa=1; PHPSESSID=8t2ndj5163ou6l724l310mcp01
    HTTP_HOST: www.oddball.co.uk
    HTTP_ACCEPT_ENCODING: gzip, deflate
    HTTP_REFERER: https://www.oddball.co.uk/perch/core/settings/diagnostics/
    HTTP_ACCEPT_LANGUAGE: en-US,en;q=0.5
    HTTP_ACCEPT: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
    HTTP_USER_AGENT: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:41.0) Gecko/20100101 Firefox/41.0
    REMOTE_HOST: 80.7.85.2
    REDIRECT_STATUS: 200
    REDIRECT_HANDLER: php56-script
    REDIRECT_REMOTE_HOST: 80.7.85.2
    FCGI_ROLE: RESPONDER
    PHP_SELF: https://www.oddball.co.uk/perch/core/settings/diagnostics/?extended
    REQUEST_TIME_FLOAT: 1444991696.6611
    REQUEST_TIME: 1444991696