LESS Function -evo-widgetfile-url does not work as expected in Verint 12

I'm using a similar template to generate CSS from LESS styles as in the Site Theme (variables.less => variables.vm), to define styles for the widget based on some environment conditions and configuration settings.

I found that "-evo-widgetfile-url" does not work as expected in Verint 12.0.3.17950. But this function working well in Verint 11.1.x versions.

Sample code to reproduce this issue:

Widget Content component code:

$core_v2_page.AddLink('stylesheet', $core_v2_widget.GetExecutedFileUrl('render-styles.less'), "%{ Position = 'AfterTheme' }")

<div class="unique-wrapper">
</div>

Widget "render-styles.less" code:

@import "-evo-widgetfile-url('variables.vm')";

Widget "variables.vm" code:

#if ($core_v2_user.Accessing.Username == $core_v2_user.AnonymousUserName)
    .unique-wrapper {
        height: 100px;
        background: blue;
    }
#else
    .unique-wrapper {
        height: 100px;
        background: green;
    }
#end

On the page where this widget placed I see the following output in the network tab for my widget style file:
@import "-evo-widgetfile-url('variables.vm')";