I'm trying to include a cc adress for my item list email link. I used this:

 "href": {
      "operator": "+",
      "operands": [
        "mailto:",
        "[email protected]",
        "?cc=",
        "[email protected]",
        "?subject=",
        "Test Subject",

The result is the following:

For some reason my subject lengthens the cc field. Any idea what goes wrong here? If I look at the code I don't see anything wrong...