ActionView::Template::Error: undefined method `to_str' for nil:NilClass

Sentry Issue: GALILEO-SEARCH-18

NoMethodError: undefined method `to_str' for nil:NilClass
  app/bento/base/bento_result_record.rb:69:in `alt_text_fallback'
    "Thumbnail for #{display_title.to_str}"
  app/views/bento/_results_inner.html.erb:15:
    fallback_alt: result.alt_text_fallback),
  app/views/bento/_results_inner.html.erb:11:in `each'
    <% response.records.each do |result| %>
  app/views/bento/_results_inner.html.erb:11:
    <% response.records.each do |result| %>
  app/views/bento/_results.erb:17:
    <%= render partial: 'bento/results_inner', locals: { response: response } %>
...
(139 additional frame(s) were not displayed)

ActionView::Template::Error: undefined method `to_str' for nil:NilClass