less.js bug

index.less

@import (reference) "./referenced.less";

out.css

@media (hover) {
}@media (hover) {
}

referenced.less

.referenced {
    // line comment is enough to reproduce it
    @media (hover) { 
        // sezam
    }
    // repeat to prove point
    @media (hover) { 
        // sezam
    }
    // but block comment is not, huh
    @media (hover) { 
        /* salabim */
    }
    // following not outputs, needs line comment
    @media (hover) { 
        color: #000000;
    }
}
// needs to be nested to fail
@media (hover) { 
    // sezam
}

less/less.js#2991