diff --git a/web/src/components/settings/ObjectMaskEditPane.tsx b/web/src/components/settings/ObjectMaskEditPane.tsx
index c898531c4..2874c8b92 100644
--- a/web/src/components/settings/ObjectMaskEditPane.tsx
+++ b/web/src/components/settings/ObjectMaskEditPane.tsx
@@ -178,6 +178,19 @@ export default function ObjectMaskEditPane({
         filteredMask.splice(index, 0, coordinates);
       }
 
+      // prevent duplicating global masks under specific object filters
+      if (!globalMask) {
+        const globalObjectMasksArray = Array.isArray(cameraConfig.objects.mask)
+          ? cameraConfig.objects.mask
+          : cameraConfig.objects.mask
+            ? [cameraConfig.objects.mask]
+            : [];
+
+        filteredMask = filteredMask.filter(
+          (mask) => !globalObjectMasksArray.includes(mask),
+        );
+      }
+
       queryString = filteredMask
         .map((pointsArray) => {
           const coordinates = flattenPoints(parseCoordinates(pointsArray)).join(