diff --git a/.github/workflows/tf-acc-test.yaml b/.github/workflows/tf-acc-test.yaml
index 5f699efe..1d11070e 100644
--- a/.github/workflows/tf-acc-test.yaml
+++ b/.github/workflows/tf-acc-test.yaml
@@ -97,9 +97,9 @@ jobs:
           echo "time=$(date --rfc-3339=ns)" >> ${GITHUB_ENV}
           end=$(date +%s%N)
           echo "end=${end}" >> ${GITHUB_ENV}
-          start=${{ steps.start_time.outputs.start }}
+          start="${{ steps.start_time.outputs.start }}"
           diff=$((end-start))
-          duration=sprintf "%s.%s" "${diff:0: -9}" "${diff: -9:3}"
+          duration=$(printf "%s.%s" "${diff:0: -9}" "${diff: -9:3}")
           echo "duration=${duration}" >> ${GITHUB_ENV}
 
       - name: Notify