<% current = current_page_preferences? %>
<li class="thredded--user-navigation--settings thredded--user-navigation--item<%= ' thredded--is-current' if current %>">
  <%= link_to current ? (messageboard ? messageboard_topics_path(messageboard) : messageboards_path)
                      : edit_preferences_path(messageboard) do %>
    <%= inline_svg 'thredded/settings.svg', class: 'thredded--icon', title: t('thredded.nav.settings') %>
    <span class="thredded--nav-text"><%= t('thredded.nav.settings') %></span>
  <% end %>
</li>

<% current = current_page_preferences? %>
<li class="thredded--user-navigation--settings thredded--user-navigation--item<%= ' thredded--is-current' if current %>">
  <%= link_to current ? (messageboard ? messageboard_topics_path(messageboard) : messageboards_path)
                      : edit_preferences_path(messageboard), rel: 'nofollow' do %>
    <%= inline_svg 'thredded/settings.svg', class: 'thredded--icon', title: t('thredded.nav.settings') %>
    <span class="thredded--nav-text"><%= t('thredded.nav.settings') %></span>
  <% end %>
</li>

Add rel=nofollow to the preferences link
Add rel=nofollow to the preferences link
