shipping_method "" cannot be serialized into Enum OrderManagementShippingMethod

[ToxicTree]

Describe the bug
We do not have a shipping_method defined on some orders/captures, making it impossible to get orders using OrderManagement.GetOrder(orderId)

Which service do you use
Order management

To Reproduce
Steps to reproduce the behavior:
Try to get orders that do not have any shipping...

Expected behavior
Get a order without shipping information (we do not care about this information)

Additional context
NETCore App 2.0, Klarna.Rest.Core 3.1.12

Exception:

ArgumentException: Must specify valid information for parsing in the string.
Newtonsoft.Json.Utilities.EnumUtils.ParseEnum(Type enumType, string value, bool disallowNumber)

JsonSerializationException: Error converting value "" to type 'Klarna.Rest.Core.Model.Enum.OrderManagementShippingMethod'. Path 'captures[0].shipping_info[0].shipping_method', line 1, position 4740.
Newtonsoft.Json.Converters.StringEnumConverter.ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)