diff --git a/pkg/kapp/diff/rebased_resource.go b/pkg/kapp/diff/rebased_resource.go
index 1ad53d027..1130d3745 100644
--- a/pkg/kapp/diff/rebased_resource.go
+++ b/pkg/kapp/diff/rebased_resource.go
@@ -38,10 +38,10 @@ func (r RebasedResource) Resource() (ctlres.Resource, error) {
 		if t.IsResourceMatching(result) {
 			// copy newRes and existingRes as they may be modified in place
 			resSources := map[ctlres.FieldCopyModSource]ctlres.Resource{
-				ctlres.FieldCopyModSourceNew:      r.newRes.DeepCopy(),
-				ctlres.FieldCopyModSourceExisting: r.existingRes.DeepCopy(),
+				ctlres.FieldCopyModSourceNew:      r.newRes,
+				ctlres.FieldCopyModSourceExisting: r.existingRes,
 				// Might be useful for more advanced rebase rules like ytt-based
-				ctlres.FieldCopyModSource("_current"): result.DeepCopy(),
+				ctlres.FieldCopyModSource("_current"): result,
 			}
 
 			err := t.ApplyFromMultiple(result, resSources)
diff --git a/pkg/kapp/resources/mod_field_copy.go b/pkg/kapp/resources/mod_field_copy.go
index b6ebe5876..4b76499b6 100644
--- a/pkg/kapp/resources/mod_field_copy.go
+++ b/pkg/kapp/resources/mod_field_copy.go
@@ -39,6 +39,7 @@ func (t FieldCopyMod) ApplyFromMultiple(res Resource, srcs map[FieldCopyModSourc
 		// Make a copy of resource, to avoid modifications
 		// that may be done even in case when there is nothing to copy
 		updatedRes := res.DeepCopy()
+		source = source.DeepCopy()
 		updated, err := t.apply(updatedRes.unstructured().Object, source.unstructured().Object, t.Path, Path{}, srcs)
 		if err != nil {
 			return fmt.Errorf("FieldCopyMod for path '%s' on resource '%s': %s", t.Path.AsString(), res.Description(), err)
@@ -198,7 +199,7 @@ func (t FieldCopyMod) copyIntoMap(obj map[string]interface{}, fullPath Path, src
 			continue
 		}
 
-		val, found, err := t.obtainValue(srcRes.unstructured().Object, fullPath)
+		val, found, err := t.obtainValue(srcRes.DeepCopy().unstructured().Object, fullPath)
 		if err != nil {
 			return false, err
 		} else if !found {