diff --git a/scripts/e2e/lib/plugin-update/corrupt-update-scenario.sh b/scripts/e2e/lib/plugin-update/corrupt-update-scenario.sh
index b5990f718b74..05d23e8b35c8 100644
--- a/scripts/e2e/lib/plugin-update/corrupt-update-scenario.sh
+++ b/scripts/e2e/lib/plugin-update/corrupt-update-scenario.sh
@@ -21,7 +21,7 @@ baseline="${OPENCLAW_UPDATE_CORRUPT_PLUGIN_BASELINE:-openclaw@latest}"
 update_timeout_seconds="$(openclaw_e2e_read_positive_int_env OPENCLAW_UPDATE_CORRUPT_PLUGIN_TIMEOUT_SECONDS 900)"
 default_update_step_timeout_seconds="$update_timeout_seconds"
 if [ "$update_timeout_seconds" -gt 60 ]; then
-  default_update_step_timeout_seconds=$((update_timeout_seconds - 30))
+  default_update_step_timeout_seconds=$((10#$update_timeout_seconds - 30))
 fi
 update_step_timeout_seconds="$(openclaw_e2e_read_positive_int_env OPENCLAW_UPDATE_CORRUPT_PLUGIN_STEP_TIMEOUT_SECONDS "$default_update_step_timeout_seconds")"
 echo "Installing baseline OpenClaw package: $baseline"
diff --git a/test/scripts/plugin-update-unchanged-docker.test.ts b/test/scripts/plugin-update-unchanged-docker.test.ts
index 8041da3f688b..41f9b49b8f2a 100644
--- a/test/scripts/plugin-update-unchanged-docker.test.ts
+++ b/test/scripts/plugin-update-unchanged-docker.test.ts
@@ -202,7 +202,7 @@ describe("plugin update unchanged Docker E2E", () => {
     );
     expect(script).toContain("OPENCLAW_UPDATE_CORRUPT_PLUGIN_STEP_TIMEOUT_SECONDS");
     expect(script).toContain(
-      'default_update_step_timeout_seconds=$((update_timeout_seconds - 30))',
+      'default_update_step_timeout_seconds=$((10#$update_timeout_seconds - 30))',
     );
     expect(script).not.toContain(
       'update_timeout_seconds="${OPENCLAW_UPDATE_CORRUPT_PLUGIN_TIMEOUT_SECONDS:-900}"',