Grammars which extend Javascript fail to parse template literals, despite the Javascript grammar doing so itself

[enquora]

The following Javascript code is correctly parsed by the grammar:

// test.js
function fact(n) {
    let res = 1;
    for (let i = 1; i <= n; i++) {
        res *= i;
    }
    return res;
}

let test_value = "hello";
let test_templated_string = `${test_value} world!`;

Any grammar which extends the Javascript generates an error when encountering template literals, despite the canonical Javascript grammar parsing all constructs properly.
Other javascript constructs are parsed properly by the extended grammar, whether any rules are present or not.