Troubleshooting Time Difference Calculation in JQL Events Code

Hi, Trying to figure out time difference between 2 events basis a common property in JQL but time is always coming null. here is the attached code. function main() { return Events({ from_date: "2024-12-27", to_date: "2024-12-27" }) .filter(function(event) { return (event.name === "transaction_started" || event.name === "payment_completed") && event.properties.bill_session_id; // Ensure bill_session_id exists }) .groupBy( ["properties.bill_session_id"], function(state, events) { if (!state) { state = { transaction_started_time: null, payment_completed_time: null }; } for (var i = 0; i < events.length; i++) { var e = events[i]; // Use event.time directly, not event.properties.time if (e.name === "transaction_started") { state.transaction_started_time = state.transaction_started_time ? Math.min(state.transaction_started_time, e.time) : e.time; } if (e.name === "payment_completed") { state.payment_completed_time = state.payment_completed_time ? Math.min(state.payment_completed_time, e.time) : e.time; } } return state; } ) .map(function(r) { var txn_time = r.value.transaction_started_time || null; var pay_time = r.value.payment_completed_time || null; var time_diff = (txn_time && pay_time) ? (pay_time - txn_time) : null; // Time difference in seconds return { bill_session_id: r.key[0], transaction_started_time: txn_time, payment_completed_time: pay_time, time_difference_seconds: time_diff }; }); } Any help is appreciated.