Arvados

When trying to use the 'Show version' or 'Report a problem' menu items on Workbench on one of our dev clusters, I get the following error on the brower's javascript console:

[Error] Failed to load resource: the server responded with a status of 422 (Unprocessable Entity) (report_issue_popup, line 0)

Checking workbench's logs I'm seeing this:

#<ActionView::Template::Error: uninitialized constant ActionView::CompiledTemplates::AppVersion
Did you mean?  ActionView::VERSION>
/var/www/arvados-workbench/current/app/views/application/_report_issue_popup.html.erb:19:in `_app_views_application__report_issue_popup_html_erb__2330610321802802077_33518400'
/var/www/arvados-workbench/shared/vendor_bundle/ruby/2.3.0/gems/actionview-5.0.7.2/lib/action_view/template.rb:159:in `block in render'
/var/www/arvados-workbench/shared/vendor_bundle/ruby/2.3.0/gems/activesupport-5.0.7.2/lib/active_support/notifications.rb:166:in `instrument'
/var/www/arvados-workbench/shared/vendor_bundle/ruby/2.3.0/gems/actionview-5.0.7.2/lib/action_view/template.rb:354:in `instrument'
[…]
/usr/lib/ruby/vendor_ruby/phusion_passenger/rack/thread_handler_extension.rb:97:in `process_request'
/usr/lib/ruby/vendor_ruby/phusion_passenger/request_handler/thread_handler.rb:152:in `accept_and_process_next_request'
/usr/lib/ruby/vendor_ruby/phusion_passenger/request_handler/thread_handler.rb:113:in `main_loop'
/usr/lib/ruby/vendor_ruby/phusion_passenger/request_handler.rb:416:in `block (3 levels) in start_threads'
/usr/lib/ruby/vendor_ruby/phusion_passenger/utils.rb:113:in `block in create_thread_and_abort_on_exception'

{"method":"GET","path":"/report_issue_popup","format":"js","controller":"ActionsController","action":"report_issue_popup","status":422,"duration":488.06,"view":0.14,"request_id":"req-v73s9v0b17x792rwg55d","params":{"action_method":"post","current_location":"https://workbench.c97qk.arvadosapi.com/users/welcome?return_to=%2F","current_path":"/users/welcome?return_to=%2F","popup_type":"version"},"@timestamp":"2019-05-21T19:06:29.394Z","@version":"1","message":"[422] GET /report_issue_popup (ActionsController#report_issue_popup)"}

It seems that this is related to the environment at which the rails app is running, because it isn't failing on arvbox or running workbench locally against one of the dev clusters.