Hope somebody can help me with the modern forms designer on a self hosted setup.

I have a client running on Laserfiche Forms Professional Version 12.0.2503.10378 where I use "DOMContentLoaded" in the JS to get a token from the URL to be used on the form.

// Get the review uuid (token) from the URL and set it into the Manager Review UUID field
document.addEventListener("DOMContentLoaded", function () {
    const url = new URL(window.location.href);
    let token = new URLSearchParams(url.search).get("token");
    console.log("Extracted token:", token);

    if (token) {
        token = token.trim();

        setTimeout(function () {
            // Target by variable name (preferred for Modern Designer)
            const field = document.querySelector("[data-var='Manager_Review_UUID'] input");

            if (field) {
                field.value = token;

                // Dispatch input event so Forms registers the change
                field.dispatchEvent(new Event("input", { bubbles: true }));
                console.log("Manager Review UUID field set with token.");
            } else {
                console.warn("Manager Review UUID field not found. Check variable name or selector.");
            }
        }, 2000); // 2000 ms = 2 seconds
    } else {
        console.log("Token is empty or not provided.");
    }
});

This code works perfectly in this version of forms, however in the latest version "Laserfiche Forms Professional Version 12.0.2509.20409" on a separate customer's server, the code does not seem to be executing.