concrete5 Environment Information
# concrete5 Version
Core Version - 8.3.1
Version Installed - 8.3.1
Database Version - 20171218000000
# concrete5 Packages
List files from set (1.0.7), Nestable Manual Nav (1.2.0), Page Redirect (2.0), Page Selector Attribute (2.0)
# concrete5 Overrides
blocks/faq/view.css, blocks/faq/view.js, blocks/faq/view.php, blocks/faq, blocks/event_list/templates/nphi/view.css, blocks/event_list/templates/nphi/view.php, blocks/event_list/templates/nphi, blocks/event_list/templates, blocks/event_list, blocks/page_title/templates/byline_NPHI.php, blocks/page_title/templates, blocks/page_title, blocks/testimonial/templates/name_on_bottom/view.php, blocks/testimonial/templates/name_on_bottom, blocks/testimonial/templates/special/view.css, blocks/testimonial/templates/special/view.php, blocks/testimonial/templates/special, blocks/testimonial/templates, blocks/testimonial, blocks/external_link/db.xml, blocks/external_link/controller.php, blocks/external_link/view.php, blocks/external_link, blocks/express_entry_list/templates/memberlist/view.css, blocks/express_entry_list/templates/memberlist/view.js, blocks/express_entry_list/templates/memberlist/view.php, blocks/express_entry_list/templates/memberlist, blocks/express_entry_list/templates/board-of-directors/view.css, blocks/express_entry_list/templates/board-of-directors/view.js, blocks/express_entry_list/templates/board-of-directors/view.php, blocks/express_entry_list/templates/board-of-directors, blocks/express_entry_list/templates/staff/view.css, blocks/express_entry_list/templates/staff/view.js, blocks/express_entry_list/templates/staff/view.php, blocks/express_entry_list/templates/staff, blocks/express_entry_list/templates/leadership/view.css, blocks/express_entry_list/templates/leadership/view.js, blocks/express_entry_list/templates/leadership/view.php, blocks/express_entry_list/templates/leadership, blocks/express_entry_list/templates, blocks/express_entry_list, blocks/feature/templates/just_a_link/view.php, blocks/feature/templates/just_a_link, blocks/feature/templates/text_only/view.php, blocks/feature/templates/text_only, blocks/feature/templates/large_head_no_button/view.css, blocks/feature/templates/large_head_no_button/view.php, blocks/feature/templates/large_head_no_button, blocks/feature/templates/icon_only/view.php, blocks/feature/templates/icon_only, blocks/feature/templates/large_head/view.css, blocks/feature/templates/large_head/view.php, blocks/feature/templates/large_head, blocks/feature/templates, blocks/feature/view.php, blocks/feature, blocks/list_files_from_set/view.php, blocks/list_files_from_set, blocks/location_map/scrapbook.php, blocks/location_map/db.xml, blocks/location_map/controller.php, blocks/location_map/js/jquery.usmap_modified.js, blocks/location_map/js/jquery.usmap.js, blocks/location_map/js/color.jquery.js, blocks/location_map/js/raphael.js, blocks/location_map/js, blocks/location_map/view.css, blocks/location_map/view.php, blocks/location_map, blocks/calendar/templates/nphi/view.css, blocks/calendar/templates/nphi/view.php, blocks/calendar/templates/nphi, blocks/calendar/templates, blocks/calendar, themes/nphi/page_theme.php, themes/nphi/description.txt, themes/nphi/default.php, themes/nphi/img/background.png, themes/nphi/img/hands.png, themes/nphi/img/concretelogin.png, themes/nphi/img, themes/nphi/homepage.php, themes/nphi/flexible.php, themes/nphi/css/styles.css, themes/nphi/css/styles_edit.css, themes/nphi/css/styles_reset.css, themes/nphi/css/styles_loggedin.css, themes/nphi/css, themes/nphi/right_sidebar.php, themes/nphi/inc/footerhtml.php, themes/nphi/inc/headerhtml.php, themes/nphi/inc/footer.php, themes/nphi/inc/script_incs.php, themes/nphi/inc/header.php, themes/nphi/inc/breadcrumb.php, themes/nphi/inc/script_incs_head.php, themes/nphi/inc, themes/nphi/scripts/cycle.jquery.js, themes/nphi/scripts/scripts.js, themes/nphi/scripts, themes/nphi/thumbnail.png, themes/nphi/view.php, themes/nphi
# concrete5 Cache Settings
Block Cache - On
Overrides Cache - On
Full Page Caching - On - If blocks on the particular page allow it.
Full Page Cache Lifetime - Every 6 hours (default setting).
# Server Software
Apache
# Server API
cgi-fcgi
# PHP Version
5.6.36
# PHP Extensions
bcmath, bz2, calendar, cgi-fcgi, Core, ctype, curl, date, dba, dom, enchant, ereg, exif, fileinfo, filter, ftp, gd, gettext, gmp, hash, iconv, imagick, imap, intl, ionCube Loader, json, ldap, libxml, mbstring, mcrypt, mysql, mysqli, mysqlnd, odbc, openssl, pcntl, pcre, PDO, pdo_mysql, PDO_ODBC, pdo_pgsql, pdo_sqlite, pgsql, Phar, posix, pspell, readline, redis, Reflection, session, SimpleXML, soap, sockets, SPL, sqlite3, standard, sysvmsg, sysvsem, sysvshm, tidy, tokenizer, xml, xmlreader, xmlrpc, xmlwriter, xsl, Zend OPcache, zip, zlib
# PHP Settings
max_execution_time - 30
log_errors_max_len - 1024
max_file_uploads - 20
max_input_nesting_level - 64
max_input_time - 60
max_input_vars - 1000
memory_limit - 264M
post_max_size - 16M
sql.safe_mode - Off
upload_max_filesize - 16M
ldap.max_links - Unlimited
mysql.max_links - Unlimited
mysql.max_persistent - Unlimited
mysqli.max_links - Unlimited
mysqli.max_persistent - Unlimited
odbc.max_links - Unlimited
odbc.max_persistent - Unlimited
pcre.backtrack_limit - 1000000
pcre.recursion_limit - 100000
pgsql.max_links - Unlimited
pgsql.max_persistent - Unlimited
session.cache_limiter - <i>no value</i>
session.gc_maxlifetime - 7200
soap.wsdl_cache_limit - 5
opcache.max_accelerated_files - 2000
opcache.max_file_size - 0
opcache.max_wasted_percentage - 5
It shouldn't have anything to do with add-on directly. I guess the js code which is responsible to display the menu pick both instances simultaneously. I recommend you, firstly, to download the latest version of add-on from Github repo, which has block unique identifier. Then, check your js code and see if you can narrow down the selector.