diff --git a/packages/tools/src/tools/annotation/AngleTool.ts b/packages/tools/src/tools/annotation/AngleTool.ts
index 48ec32893..f83499802 100644
--- a/packages/tools/src/tools/annotation/AngleTool.ts
+++ b/packages/tools/src/tools/annotation/AngleTool.ts
@@ -658,7 +658,10 @@ class AngleTool extends AnnotationTool {
       const canvasCoordinates = points.map((p) => viewport.worldToCanvas(p));
 
       // WE HAVE TO CACHE STATS BEFORE FETCHING TEXT
-      if (!data.cachedStats[targetId]) {
+      if (
+        !data.cachedStats[targetId] ||
+        data.cachedStats[targetId].angle == null
+      ) {
         data.cachedStats[targetId] = {
           angle: null,
         };
diff --git a/packages/tools/src/tools/annotation/BidirectionalTool.ts b/packages/tools/src/tools/annotation/BidirectionalTool.ts
index b9928aed8..066fa496b 100644
--- a/packages/tools/src/tools/annotation/BidirectionalTool.ts
+++ b/packages/tools/src/tools/annotation/BidirectionalTool.ts
@@ -1073,7 +1073,7 @@ class BidirectionalTool extends AnnotationTool {
       // force to recalculate the stats from the points
       if (
         !data.cachedStats[targetId] ||
-        data.cachedStats[targetId].unit === undefined
+        data.cachedStats[targetId].unit == null
       ) {
         data.cachedStats[targetId] = {
           length: null,
diff --git a/packages/tools/src/tools/annotation/CircleROITool.ts b/packages/tools/src/tools/annotation/CircleROITool.ts
index 11abb0df3..a88f251a4 100644
--- a/packages/tools/src/tools/annotation/CircleROITool.ts
+++ b/packages/tools/src/tools/annotation/CircleROITool.ts
@@ -692,7 +692,7 @@ class CircleROITool extends AnnotationTool {
       // force to recalculate the stats from the points
       if (
         !data.cachedStats[targetId] ||
-        data.cachedStats[targetId].areaUnit === undefined
+        data.cachedStats[targetId].areaUnit == null
       ) {
         data.cachedStats[targetId] = {
           Modality: null,
diff --git a/packages/tools/src/tools/annotation/CobbAngleTool.ts b/packages/tools/src/tools/annotation/CobbAngleTool.ts
index ad5d3abdc..690d28524 100644
--- a/packages/tools/src/tools/annotation/CobbAngleTool.ts
+++ b/packages/tools/src/tools/annotation/CobbAngleTool.ts
@@ -674,7 +674,10 @@ class CobbAngleTool extends AnnotationTool {
       const canvasCoordinates = points.map((p) => viewport.worldToCanvas(p));
 
       // WE HAVE TO CACHE STATS BEFORE FETCHING TEXT
-      if (!data.cachedStats[targetId]) {
+      if (
+        !data.cachedStats[targetId] ||
+        data.cachedStats[targetId].angle == null
+      ) {
         data.cachedStats[targetId] = {
           angle: null,
         };
diff --git a/packages/tools/src/tools/annotation/DragProbeTool.ts b/packages/tools/src/tools/annotation/DragProbeTool.ts
index 646eb3614..6bae955fd 100644
--- a/packages/tools/src/tools/annotation/DragProbeTool.ts
+++ b/packages/tools/src/tools/annotation/DragProbeTool.ts
@@ -166,7 +166,10 @@ class DragProbeTool extends ProbeTool {
       ),
     };
 
-    if (!data.cachedStats[targetId]) {
+    if (
+      !data.cachedStats[targetId] ||
+      data.cachedStats[targetId].value == null
+    ) {
       data.cachedStats[targetId] = {
         Modality: null,
         index: null,
diff --git a/packages/tools/src/tools/annotation/EllipticalROITool.ts b/packages/tools/src/tools/annotation/EllipticalROITool.ts
index c8cf0e4c6..0d1981b98 100644
--- a/packages/tools/src/tools/annotation/EllipticalROITool.ts
+++ b/packages/tools/src/tools/annotation/EllipticalROITool.ts
@@ -814,7 +814,7 @@ class EllipticalROITool extends AnnotationTool {
       // force to recalculate the stats from the points
       if (
         !data.cachedStats[targetId] ||
-        data.cachedStats[targetId].areaUnit === undefined
+        data.cachedStats[targetId].areaUnit == null
       ) {
         data.cachedStats[targetId] = {
           Modality: null,
diff --git a/packages/tools/src/tools/annotation/LengthTool.ts b/packages/tools/src/tools/annotation/LengthTool.ts
index 353b68b5e..3eba6bd69 100644
--- a/packages/tools/src/tools/annotation/LengthTool.ts
+++ b/packages/tools/src/tools/annotation/LengthTool.ts
@@ -662,7 +662,7 @@ class LengthTool extends AnnotationTool {
       // force to recalculate the stats from the points
       if (
         !data.cachedStats[targetId] ||
-        data.cachedStats[targetId].unit === undefined
+        data.cachedStats[targetId].unit == null
       ) {
         data.cachedStats[targetId] = {
           length: null,
diff --git a/packages/tools/src/tools/annotation/PlanarFreehandROITool.ts b/packages/tools/src/tools/annotation/PlanarFreehandROITool.ts
index 0ecfc6baa..d712c14b6 100644
--- a/packages/tools/src/tools/annotation/PlanarFreehandROITool.ts
+++ b/packages/tools/src/tools/annotation/PlanarFreehandROITool.ts
@@ -691,7 +691,7 @@ class PlanarFreehandROITool extends AnnotationTool {
         const { data } = annotation;
         if (
           !data.cachedStats[targetId] ||
-          data.cachedStats[targetId].areaUnit === undefined
+          data.cachedStats[targetId].areaUnit == null
         ) {
           data.cachedStats[targetId] = {
             Modality: null,
diff --git a/packages/tools/src/tools/annotation/ProbeTool.ts b/packages/tools/src/tools/annotation/ProbeTool.ts
index 23ed07f6d..f9049cf2e 100644
--- a/packages/tools/src/tools/annotation/ProbeTool.ts
+++ b/packages/tools/src/tools/annotation/ProbeTool.ts
@@ -452,7 +452,10 @@ class ProbeTool extends AnnotationTool {
         ),
       };
 
-      if (!data.cachedStats[targetId]) {
+      if (
+        !data.cachedStats[targetId] ||
+        data.cachedStats[targetId].value == null
+      ) {
         data.cachedStats[targetId] = {
           Modality: null,
           index: null,
diff --git a/packages/tools/src/tools/annotation/RectangleROITool.ts b/packages/tools/src/tools/annotation/RectangleROITool.ts
index 49272d911..a2479cc4b 100644
--- a/packages/tools/src/tools/annotation/RectangleROITool.ts
+++ b/packages/tools/src/tools/annotation/RectangleROITool.ts
@@ -673,7 +673,7 @@ class RectangleROITool extends AnnotationTool {
       // force to recalculate the stats from the points
       if (
         !data.cachedStats[targetId] ||
-        data.cachedStats[targetId].areaUnit === undefined
+        data.cachedStats[targetId].areaUnit == null
       ) {
         data.cachedStats[targetId] = {
           Modality: null,
diff --git a/packages/tools/src/tools/displayTools/Contour/contourDisplay.ts b/packages/tools/src/tools/displayTools/Contour/contourDisplay.ts
index 1add8e631..aa7bca815 100644
--- a/packages/tools/src/tools/displayTools/Contour/contourDisplay.ts
+++ b/packages/tools/src/tools/displayTools/Contour/contourDisplay.ts
@@ -2,6 +2,7 @@ import {
   getEnabledElementByIds,
   Types,
   utilities as csUtils,
+  StackViewport,
 } from '@cornerstonejs/core';
 
 import Representations from '../../../enums/SegmentationRepresentations';
@@ -128,6 +129,13 @@ async function render(
   const contourData = segmentation.representationData[Representations.Contour];
   const { geometryIds } = contourData;
 
+
+  // We don't have a good way to handle stack viewports for contours at the moment.
+  // Plus, if we add a segmentation to one viewport, it gets added to all the viewports in the toolGroup too.
+  if (viewport instanceof StackViewport) {
+    return;
+  }
+
   if (!geometryIds?.length) {
     console.warn(
       `No contours found for segmentationId ${segmentationId}. Skipping render.`