Include/Exclude labels do not work when the key word is not used in contentbylabel macro

contentbylabel macro has 'label' as a required parameter; however you can leave out the key word 'label' and just specify the list of label values.

{contentbylabel:goodpage}

You can also include/exclude matches by using +/- before the label values.

{contentbylabel:label=+goodpage,-badpage}

However, these do not work at the same time; the following will give 'No content found for label(s) +goodpage':

{contentbylabel:+goodpage}