Can't remove phonenumber field from contact

Short demo script:

    navigator.contacts.find(["*"], function (contacts) {
        // Pick a contact
        // (Make sure the contact has more than two phoneNumberFields)
        var myContact = contacts[4]; 

        // Remove the second phone number
        delete myContact.phoneNumbers[1];

        myContact.save(function () {
            console.log("Success");
            /// You will see, that the contact still has all it's previous phone numbers
        }, function () {
            console.error("error while saving");
        });
        
    }, function () {
        console.error("Could not access conacts.");
    });

Let's say a existing contact that I've retrieved from the system has two or more phone number fields. When I remove one of the both contact fields from the phoneNumbers array and then save the contact, it still has all numbers on the device. When I re-retrieve the contact it has both numbers again. (Tested on iOS 9.3 with plugin version 2.0.1)

I can't find any hint in the documentation if I do something wrong or if the plugin is behaving wrong.

I have created a demo script, which reproduces the issue. You can use it for testing:
http://pastebin.com/XRdREL3Y
You might want to remove line 25 which removes the contact in the end.

This SO Question might be related to the issue: http://stackoverflow.com/questions/35698798/cordova-contacts-plugin-contact-data-is-duplicating-instead-of-overwriting-conta?rq=1