diff --git a/backend/src/templateFormatter.ts b/backend/src/templateFormatter.ts
index e51506c4..299efb2e 100644
--- a/backend/src/templateFormatter.ts
+++ b/backend/src/templateFormatter.ts
@@ -353,6 +353,7 @@ const baseValues = {
     return [...args].join("");
   },
   concatArr(arr, separator = "") {
+    if (!Array.isArray(arr)) return "";
     return arr.join(separator);
   },
   eq(...args) {
diff --git a/docker/production/backend/Dockerfile b/docker/production/backend/Dockerfile
index 590c44cf..63da6d1b 100644
--- a/docker/production/backend/Dockerfile
+++ b/docker/production/backend/Dockerfile
@@ -4,6 +4,4 @@ USER node
 COPY --chown=node:node . /zeppelin
 
 WORKDIR /zeppelin/backend
-RUN ls -lah
-RUN pwd
 RUN npm ci && npm run build