Please try to execute the following snippet in the Rails Console and post the output here:
ticket = Ticket.find(106081)
ticket.search_index_attribute_lookup.keys.each do |k|
relation_class = ticket.search_index_attribute_method(k)
next if !relation_class
begin
relation_model = relation_class.lookup(id: ticket.attributes[k])
rescue
puts "Error looking up #{k} => #{ticket.attributes[k]}, #{relation_class}"
end
end