repeating error related to "conditionally_restrict"

BEing reported in Slack #app-exeptions channel. dlg-exhibits-staging is the hook name, but the error shows hostname is prod. Should probably figure out why that is as well.

Exception undefined method 'slug' for nil:NilClass Hostname spotlight-prod Backtrace

app/helpers/image_protection_helper.rb:5:in conditionally_restrict' app/views/catalog/_openseadragon_default.html.erb:25:in _app_views_catalog__openseadragon_default_html_erb__1351359739581981976_47328669179280' app/views/catalog/show.html.erb:5:in _app_views_catalog_show_html_erb___1631617904628462685_47328673169140' /app/ruby/2.6.6/lib/ruby/2.6.0/benchmark.rb:308:in realtime'