diff --git a/modules/core/include/opencv2/core/mat.hpp b/modules/core/include/opencv2/core/mat.hpp
index 9fdc5a9929..65408d5e7c 100644
--- a/modules/core/include/opencv2/core/mat.hpp
+++ b/modules/core/include/opencv2/core/mat.hpp
@@ -357,6 +357,9 @@ public:
 
     void assign(const UMat& u) const;
     void assign(const Mat& m) const;
+
+    void assign(const std::vector<UMat>& v) const;
+    void assign(const std::vector<Mat>& v) const;
 };
 
 
diff --git a/modules/core/src/matrix.cpp b/modules/core/src/matrix.cpp
index 0208a71894..a85effc4c8 100644
--- a/modules/core/src/matrix.cpp
+++ b/modules/core/src/matrix.cpp
@@ -3053,6 +3053,82 @@ void _OutputArray::assign(const Mat& m) const
 }
 
 
+void _OutputArray::assign(const std::vector<UMat>& v) const
+{
+    int k = kind();
+    if (k == STD_VECTOR_UMAT)
+    {
+        std::vector<UMat>& this_v = *(std::vector<UMat>*)obj;
+        CV_Assert(this_v.size() == v.size());
+
+        for (size_t i = 0; i < v.size(); i++)
+        {
+            const UMat& m = v[i];
+            UMat& this_m = this_v[i];
+            if (this_m.u != NULL && this_m.u == m.u)
+                continue; // same object (see dnn::Layer::forward_fallback)
+            m.copyTo(this_m);
+        }
+    }
+    else if (k == STD_VECTOR_MAT)
+    {
+        std::vector<Mat>& this_v = *(std::vector<Mat>*)obj;
+        CV_Assert(this_v.size() == v.size());
+
+        for (size_t i = 0; i < v.size(); i++)
+        {
+            const UMat& m = v[i];
+            Mat& this_m = this_v[i];
+            if (this_m.u != NULL && this_m.u == m.u)
+                continue; // same object (see dnn::Layer::forward_fallback)
+            m.copyTo(this_m);
+        }
+    }
+    else
+    {
+        CV_Error(Error::StsNotImplemented, "");
+    }
+}
+
+
+void _OutputArray::assign(const std::vector<Mat>& v) const
+{
+    int k = kind();
+    if (k == STD_VECTOR_UMAT)
+    {
+        std::vector<UMat>& this_v = *(std::vector<UMat>*)obj;
+        CV_Assert(this_v.size() == v.size());
+
+        for (size_t i = 0; i < v.size(); i++)
+        {
+            const Mat& m = v[i];
+            UMat& this_m = this_v[i];
+            if (this_m.u != NULL && this_m.u == m.u)
+                continue; // same object (see dnn::Layer::forward_fallback)
+            m.copyTo(this_m);
+        }
+    }
+    else if (k == STD_VECTOR_MAT)
+    {
+        std::vector<Mat>& this_v = *(std::vector<Mat>*)obj;
+        CV_Assert(this_v.size() == v.size());
+
+        for (size_t i = 0; i < v.size(); i++)
+        {
+            const Mat& m = v[i];
+            Mat& this_m = this_v[i];
+            if (this_m.u != NULL && this_m.u == m.u)
+                continue; // same object (see dnn::Layer::forward_fallback)
+            m.copyTo(this_m);
+        }
+    }
+    else
+    {
+        CV_Error(Error::StsNotImplemented, "");
+    }
+}
+
+
 static _InputOutputArray _none;
 InputOutputArray noArray() { return _none; }
 
diff --git a/modules/dnn/src/dnn.cpp b/modules/dnn/src/dnn.cpp
index 40edf7aa1b..4faffe1439 100644
--- a/modules/dnn/src/dnn.cpp
+++ b/modules/dnn/src/dnn.cpp
@@ -2381,6 +2381,10 @@ void Layer::forward_fallback(InputArrayOfArrays inputs_arr, OutputArrayOfArrays
         inputs[i] = &inpvec[i];
 
     this->forward(inputs, outputs, internals);
+
+    // sync results back
+    outputs_arr.assign(outputs);
+    internals_arr.assign(internals);
 }
 
 void Layer::run(const std::vector<Mat> &inputs, std::vector<Mat> &outputs, std::vector<Mat> &internals)