Fix client-side marshaller to work with unsupported elements roundtrip

2019 Week 14-16, 2019 Week 17-19, 2019 Week 20-22, 2019 Week 23-25, 2019 Week 26-28, 2019 Week 32-34, 2019 Week 35-37, 2019 Week 38-40 (from Sep 16), 2019 Week 41-43 (from Okt 7)