In the Web UI in Puppet classes I tried to search all classes that are used by some host. I searched 'set? host'

ActiveRecord::StatementInvalid
PG::Error: ERROR: missing FROM-clause entry for table "hosts" LINE 1: ...puppetclasses"."id" FROM "puppetclasses" WHERE (("hosts"."n... ^ : SELECT "puppetclasses"."id" FROM "puppetclasses" WHERE (("hosts"."name" IS NOT NULL)) ORDER BY puppetclasses.name LIMIT 20 OFFSET 0
app/controllers/puppetclasses_controller.rb:17:in `index'
app/models/concerns/foreman/thread_session.rb:33:in `clear_thread'