diff --git a/spine-c/spine-c/src/spine/Animation.c b/spine-c/spine-c/src/spine/Animation.c
index 27c963cd7..b2700e014 100644
--- a/spine-c/spine-c/src/spine/Animation.c
+++ b/spine-c/spine-c/src/spine/Animation.c
@@ -655,8 +655,8 @@ void _spScaleTimeline_apply(spTimeline *timeline, spSkeleton *skeleton, float la
 					bone->scaleY = by + (ABS(y) * SIGNUM(by) - by) * alpha;
 					break;
 				case SP_MIX_BLEND_ADD:
-					bone->scaleX = (x - bone->data->scaleX) * alpha;
-					bone->scaleY = (y - bone->data->scaleY) * alpha;
+					bone->scaleX += (x - bone->data->scaleX) * alpha;
+					bone->scaleY += (y - bone->data->scaleY) * alpha;
 			}
 		} else {
 			switch (blend) {
@@ -748,7 +748,7 @@ void _spScaleXTimeline_apply(spTimeline *timeline, spSkeleton *skeleton, float l
 					bone->scaleX = bx + (ABS(x) * SIGNUM(bx) - bx) * alpha;
 					break;
 				case SP_MIX_BLEND_ADD:
-					bone->scaleX = (x - bone->data->scaleX) * alpha;
+					bone->scaleX += (x - bone->data->scaleX) * alpha;
 			}
 		} else {
 			switch (blend) {
@@ -834,7 +834,7 @@ void _spScaleYTimeline_apply(spTimeline *timeline, spSkeleton *skeleton, float l
 					bone->scaleY = by + (ABS(y) * SIGNUM(by) - by) * alpha;
 					break;
 				case SP_MIX_BLEND_ADD:
-					bone->scaleY = (y - bone->data->scaleY) * alpha;
+					bone->scaleY += (y - bone->data->scaleY) * alpha;
 			}
 		} else {
 			switch (blend) {
@@ -1756,7 +1756,7 @@ void _spDeformTimeline_apply(
 		spTimeline *timeline, spSkeleton *skeleton, float lastTime, float time, spEvent **firedEvents,
 		int *eventsCount, float alpha, spMixBlend blend, spMixDirection direction) {
 	int frame, i, vertexCount;
-	float percent, frameTime;
+	float percent;
 	const float *prevVertices;
 	const float *nextVertices;
 	float *frames;
@@ -1892,7 +1892,6 @@ void _spDeformTimeline_apply(
 	percent = _spDeformTimeline_getCurvePercent(self, time, frame);
 	prevVertices = frameVertices[frame];
 	nextVertices = frameVertices[frame + 1];
-	frameTime = frames[frame];
 
 	if (alpha == 1) {
 		if (blend == SP_MIX_BLEND_ADD) {
diff --git a/spine-cpp/spine-cpp/src/spine/ScaleTimeline.cpp b/spine-cpp/spine-cpp/src/spine/ScaleTimeline.cpp
index 0c9b554ce..3e5ac8c61 100644
--- a/spine-cpp/spine-cpp/src/spine/ScaleTimeline.cpp
+++ b/spine-cpp/spine-cpp/src/spine/ScaleTimeline.cpp
@@ -131,8 +131,8 @@ void ScaleTimeline::apply(Skeleton &skeleton, float lastTime, float time, Vector
 					bone->_scaleY = by + (MathUtil::abs(y) * MathUtil::sign(by) - by) * alpha;
 					break;
 				case MixBlend_Add:
-					bone->_scaleX = (x - bone->_data._scaleX) * alpha;
-					bone->_scaleY = (y - bone->_data._scaleY) * alpha;
+					bone->_scaleX += (x - bone->_data._scaleX) * alpha;
+					bone->_scaleY += (y - bone->_data._scaleY) * alpha;
 			}
 		} else {
 			switch (blend) {
@@ -210,7 +210,7 @@ void ScaleXTimeline::apply(Skeleton &skeleton, float lastTime, float time, Vecto
 					bone->_scaleX = bx + (MathUtil::abs(x) * MathUtil::sign(bx) - bx) * alpha;
 					break;
 				case MixBlend_Add:
-					bone->_scaleX = (x - bone->_data._scaleX) * alpha;
+					bone->_scaleX += (x - bone->_data._scaleX) * alpha;
 			}
 		} else {
 			switch (blend) {
@@ -283,7 +283,7 @@ void ScaleYTimeline::apply(Skeleton &skeleton, float lastTime, float time, Vecto
 					bone->_scaleY = by + (MathUtil::abs(y) * MathUtil::sign(by) - by) * alpha;
 					break;
 				case MixBlend_Add:
-					bone->_scaleY = (y - bone->_data._scaleY) * alpha;
+					bone->_scaleY += (y - bone->_data._scaleY) * alpha;
 			}
 		} else {
 			switch (blend) {
diff --git a/spine-ts/spine-core/src/Animation.ts b/spine-ts/spine-core/src/Animation.ts
index 88cd0d465..510d92671 100644
--- a/spine-ts/spine-core/src/Animation.ts
+++ b/spine-ts/spine-core/src/Animation.ts
@@ -626,8 +626,8 @@ export class ScaleTimeline extends CurveTimeline2 implements BoneTimeline {
 						bone.scaleY = by + (Math.abs(y) * MathUtils.signum(by) - by) * alpha;
 						break;
 					case MixBlend.add:
-						bone.scaleX = (x - bone.data.scaleX) * alpha;
-						bone.scaleY = (y - bone.data.scaleY) * alpha;
+						bone.scaleX += (x - bone.data.scaleX) * alpha;
+						bone.scaleY += (y - bone.data.scaleY) * alpha;
 				}
 			} else {
 				switch (blend) {
@@ -699,7 +699,7 @@ export class ScaleXTimeline extends CurveTimeline1 implements BoneTimeline {
 						bone.scaleX = bx + (Math.abs(x) * MathUtils.signum(bx) - bx) * alpha;
 						break;
 					case MixBlend.add:
-						bone.scaleX = (x - bone.data.scaleX) * alpha;
+						bone.scaleX += (x - bone.data.scaleX) * alpha;
 				}
 			} else {
 				switch (blend) {
@@ -766,7 +766,7 @@ export class ScaleYTimeline extends CurveTimeline1 implements BoneTimeline {
 						bone.scaleY = by + (Math.abs(y) * MathUtils.signum(by) - by) * alpha;
 						break;
 					case MixBlend.add:
-						bone.scaleY = (y - bone.data.scaleY) * alpha;
+						bone.scaleY += (y - bone.data.scaleY) * alpha;
 				}
 			} else {
 				switch (blend) {