When trying to load a composite gradle project into netbeans an unexpeced exception occours with message 'Invalig GAV format' referring to the included project.
A dialog is opened also that some problems are to be resolved: priming build required, however hitting the resolve button does nothing (on other projects the project can be set to be a trusted one this way).
Allow gradle execution settings option is set to Always.
The included project (which is not a composite one) can be opened successfully.
The composite project can be built from command line, also can be loaded in netbeans 12.0.