It happens that the CLI does a custom parsing of the value in case ModelNode.fromString fails (whatever the exception).
The issue is that the custom parsing doesn't follow the ModelNode parsing syntax and parse everything as String. So the resulting ModelNode that is serialised and sent to the server has been transformed.

I am surprised that we don't have more of such failures. For example, when numbers are located inside custom complex structure such as:

that will be sent as an OBJECT containing a STRING although the valid DMR syntax

would be sent as an OBJECT containing an INT.

Some server side subsystems are smart enough to call into asXXX methods and not check the type?