The API design is slightly different than the JSON encoded project file design for project properties. While the API returns the specific properties from config/v1/project/, the JSON serialization of the project file will store the properties in the "client_interfaces" key as an array of the "interfaces" and their associated properties.
Right now, if the LoadProject method is executed to load the full project (config/v1/project?content=serialize) the client_interfaces are received as dynamic properties. If the LoadProject is executed to just access the project properties, each project property will be a unique dynamic property.
LoadProject without full load or a pre v6.17/1.10 version of Kepware:

LoadProject with full load:
