Grunt watch plugin does not display UglifyJS abort message

grunt-contrib-watch plugin provides nice auto-build feature but in some occasions does not display warning message from tasks, here is my grunt.js:

    min: {
        app: {
            src: [
                'some.js',
            ],
            dest: 'some.min.js'
        },
    }

    watch: {
        app: {
            files: 'some.js',
            tasks: ['min:app']
        },
    }

if source is fine, that everything goes smoothly; however when UglifyJS aborts:

run grunt min:app directly

Running "min:app" (min) task
Minifying with UglifyJS...ERROR
[L360:C46] Unexpected token name, expected punc (position: 8529)
<WARN> UglifyJS found errors. Use --force to continue. </WARN>

Aborted due to warnings.

auto-build via watch plugin

Waiting...OK
>> File "some.js" changed.
Running "min:app" (min) task

so there is no way to know if build is successful without looking at output itself.

similar setup with css less does display error to CLI, I am wondering if there is something I need to pass to grunt/watch plugin/uglify to makes it work?