LoadError: /var/www/discourse/vendor/bundle/ruby/2.4.0/gems/mini_racer-0.1.11/lib/mini_racer_extension.so: undefined symbol: _ZTIN2v811ArrayBuffer9AllocatorE - /var/www/discourse/vendor/bundle/ruby/2.4.0/gems/mini_racer-0.1.11/lib/mini_racer_extension.so
Looks like an error in one of the javascript files.
Can you try disabling all the plugins and adding them back one by one?