diff --git a/scripts/nightly-pipeline-scheduler.sh b/scripts/nightly-pipeline-scheduler.sh
index d1b546d8..07895392 100644
--- a/scripts/nightly-pipeline-scheduler.sh
+++ b/scripts/nightly-pipeline-scheduler.sh
@@ -169,10 +169,16 @@ else:
 
 
 reset_stale_states() {
-    python3 -c "
+    # Delegate to standalone script (fixes #650: inline Python $STATE_FILE escaping bug)
+    local script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+    if [[ -f "$script_dir/reset_pipeline_state.py" ]]; then
+        python3 "$script_dir/reset_pipeline_state.py" --state-file "$STATE_FILE"
+    else
+        # Fallback: inline reset with proper variable expansion
+        python3 -c "
 import json, os
 from datetime import datetime, timezone, timedelta
-path = '\$STATE_FILE'
+path = '$STATE_FILE'
 if not os.path.exists(path):
     exit(0)
 with open(path) as f:
@@ -200,6 +206,7 @@ if stale:
         json.dump(d, f, indent=2)
     print('Reset stale pipelines: ' + ', '.join(stale))
 " 2>/dev/null
+    fi
 }
 
 check_dependency() {