diff --git a/frontend/src/lib/components/booking/BookingFlow.svelte b/frontend/src/lib/components/booking/BookingFlow.svelte
index e40d367..e019f69 100644
--- a/frontend/src/lib/components/booking/BookingFlow.svelte
+++ b/frontend/src/lib/components/booking/BookingFlow.svelte
@@ -554,15 +554,16 @@
 
 			if (isAvailable) {
 				if (currentUnavailableStart !== null) {
-					// Use the end time of the last available slot as the start of unavailable period
-					const unavailableStartTime = lastAvailableEndTime || currentUnavailableStart;
 					const groupEndTime = calculatePreviousTime(timeStr);
-					groupedSlots.push({
-						type: 'unavailable',
-						startTime: unavailableStartTime,
-						endTime: groupEndTime,
-						isGrouped: true
-					});
+					const unavailableStartTime = currentUnavailableStart || lastAvailableEndTime;
+					if (unavailableStartTime && timeToMinutes(unavailableStartTime) < timeToMinutes(groupEndTime)) {
+						groupedSlots.push({
+							type: 'unavailable',
+							startTime: unavailableStartTime,
+							endTime: groupEndTime,
+							isGrouped: true
+						});
+					}
 					currentUnavailableStart = null;
 				}