diff --git a/package.json b/package.json
index adb82b4..72e81b2 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "my-weekly-todo-list",
-  "version": "1.72.1",
+  "version": "1.72.2",
   "description": "A web-based weekly task management application that organizes to-dos and calendar events in a single, intuitive weekly view",
   "main": "index.js",
   "scripts": {
diff --git a/src/components/WeeklyView.tsx b/src/components/WeeklyView.tsx
index 79ebea1..4593465 100644
--- a/src/components/WeeklyView.tsx
+++ b/src/components/WeeklyView.tsx
@@ -4082,31 +4082,40 @@ export default function WeeklyView() {
 
             for (const task of overdue) {
                 const targetSlot = task.startTime || "09:00"; // Default to 9am if no time
+                const taskDuration = task.duration || effectiveCellDuration;
 
-                // Collision detection
+                // Collision detection — checks task duration overlap, not just exact slot match
                 const isBlocked = (date: Date, slot: string, tasksToCheck: Task[]) => {
-                    // Check other tasks in the updated list
-                    const taskConflict = tasksToCheck.find(
-                        (t) =>
-                            t.id !== task.id &&
-                            t.scheduledDate &&
-                            formatDateToISO(new Date(t.scheduledDate)) ===
-                            formatDateToISO(date) &&
-                            t.startTime === slot,
-                    );
+                    const dateStr = formatDateToISO(date);
+                    const [h, m] = slot.split(":").map(Number);
+                    const slotStart = h * 60 + m;
+                    const slotEnd = slotStart + taskDuration;
+
+                    // Check other tasks (duration-aware overlap)
+                    const taskConflict = tasksToCheck.some((t) => {
+                        if (t.id === task.id || !t.startTime || t.completed) return false;
+                        if (t.parentTaskId) return false;
+                        const tDateStr = t.scheduledDate
+                            ? (typeof t.scheduledDate === "string" ? t.scheduledDate.substring(0, 10) : formatDateToISO(new Date(t.scheduledDate)))
+                            : null;
+                        if (tDateStr !== dateStr) return false;
+                        const [th, tm] = t.startTime.split(":").map(Number);
+                        const tStart = th * 60 + tm;
+                        const tEnd = tStart + (t.duration || effectiveCellDuration);
+                        return slotStart < tEnd && slotEnd > tStart;
+                    });
                     if (taskConflict) return true;
 
                     // Check calendar events
-                    const [h, m] = slot.split(":").map(Number);
-                    const slotStart = new Date(date);
-                    slotStart.setHours(h, m, 0, 0);
-                    const slotEnd = new Date(slotStart);
-                    slotEnd.setMinutes(slotEnd.getMinutes() + effectiveCellDuration);
+                    const slotStartDate = new Date(date);
+                    slotStartDate.setHours(h, m, 0, 0);
+                    const slotEndDate = new Date(slotStartDate);
+                    slotEndDate.setMinutes(slotEndDate.getMinutes() + taskDuration);
 
                     return dailyEvents.some((event) => {
                         const eventStart = new Date(event.startTime);
                         const eventEnd = new Date(event.endTime);
-                        return slotStart < eventEnd && slotEnd > eventStart;
+                        return slotStartDate < eventEnd && slotEndDate > eventStart;
                     });
                 };