diff --git a/.github/workflows/unit-test.yaml b/.github/workflows/unit-test.yaml
index 4e5ac17..2b933e1 100644
--- a/.github/workflows/unit-test.yaml
+++ b/.github/workflows/unit-test.yaml
@@ -51,7 +51,7 @@ jobs:
           submodules: true
 
       - name: Cache Go Dependencies
-        uses: actions/cache@v2
+        uses: actions/cache@v3
         with:
           path: .work/pkg
           key: ${{ runner.os }}-pkg-${{ hashFiles('**/go.sum') }}
diff --git a/pkg/context/context.go b/pkg/context/context.go
index 3540caf..21aedcb 100644
--- a/pkg/context/context.go
+++ b/pkg/context/context.go
@@ -33,7 +33,6 @@ import (
 	"k8s.io/apimachinery/pkg/types"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 
-	"github.com/kubevela/pkg/cue/util"
 	"github.com/kubevela/pkg/util/rand"
 	"github.com/kubevela/pkg/util/singleton"
 	"github.com/kubevela/workflow/pkg/cue/model/sets"
@@ -160,7 +159,7 @@ func (wf *WorkflowContext) Commit(ctx context.Context) error {
 }
 
 func (wf *WorkflowContext) writeToStore() error {
-	varStr, err := util.ToString(wf.vars)
+	varStr, err := sets.ToString(wf.vars)
 	if err != nil {
 		return err
 	}
diff --git a/pkg/hooks/data_passing.go b/pkg/hooks/data_passing.go
index 0b7de8b..0a1507a 100644
--- a/pkg/hooks/data_passing.go
+++ b/pkg/hooks/data_passing.go
@@ -64,10 +64,15 @@ func Output(ctx wfContext.Context, taskValue cue.Value, step v1alpha1.WorkflowSt
 		SetAdditionalNameInStatus(stepStatus, step.Name, step.Properties, status)
 		for _, output := range step.Outputs {
 			v, err := value.LookupValueByScript(taskValue, output.ValueFrom)
-			if err != nil && strings.Contains(err.Error(), "not exist") && !strings.Contains(output.ValueFrom, "$returns.") {
-				parts := strings.Split(output.ValueFrom, ".")
+			if (err != nil && strings.Contains(err.Error(), "not exist") || v.Err() != nil) && !strings.Contains(output.ValueFrom, "$returns.") {
+				parts := strings.Split(output.ValueFrom, "output.")
 				if len(parts) > 1 {
-					v, err = value.LookupValueByScript(taskValue, fmt.Sprintf("%s.$returns.%s", parts[0], strings.Join(parts[1:], ".")))
+					if parts[0] == "" {
+						v, err = value.LookupValueByScript(taskValue, fmt.Sprintf("output.$returns.%s", strings.Join(parts[1:], ".")))
+					} else {
+						v, err = value.LookupValueByScript(taskValue, fmt.Sprintf("%soutput.$returns.%s", parts[0], strings.Join(parts[1:], ".")))
+					}
+
 				} else {
 					v, err = value.LookupValueByScript(taskValue, fmt.Sprintf("%s.$returns", output.ValueFrom))
 				}
diff --git a/pkg/hooks/data_passing_test.go b/pkg/hooks/data_passing_test.go
index 32c92bc..4585c2b 100644
--- a/pkg/hooks/data_passing_test.go
+++ b/pkg/hooks/data_passing_test.go
@@ -138,7 +138,6 @@ func TestOutput(t *testing.T) {
 	r.Equal(int(resultInt), 99)
 	r.Equal(stepStatus["mystep"].Phase, v1alpha1.WorkflowStepPhaseSucceeded)
 
-
 	taskValue = cuectx.CompileString(`output: $returns: score: 99`)
 	stepStatus = make(map[string]v1alpha1.StepStatus)
 	err = Output(wfCtx, taskValue, v1alpha1.WorkflowStep{