diff --git a/scripts/run_behave_parallel.py b/scripts/run_behave_parallel.py
index b3d6e4d80..0731a103a 100644
--- a/scripts/run_behave_parallel.py
+++ b/scripts/run_behave_parallel.py
@@ -23,6 +23,7 @@ import argparse
 import io
 import multiprocessing
 import os
+import subprocess
 import sys
 import time
 import traceback
@@ -32,6 +33,50 @@ from typing import Any
 
 DEFAULT_FEATURE_ROOT = "features/"
 
+
+def _is_btrfs_or_overlayfs() -> bool:
+    fs_targets = {"btrfs", "overlay"}
+
+    try:
+        result = subprocess.run(
+            ["stat", "-f", "-c", "%T", "."],
+            check=True,
+            capture_output=True,
+            text=True,
+        )
+    except (OSError, subprocess.SubprocessError):
+        pass
+    else:
+        fs_type = result.stdout.strip().lower()
+        return fs_type in fs_targets
+
+    try:
+        current_path = os.path.realpath(".")
+        best_match_len = -1
+        best_fs_type: str | None = None
+        with open("/proc/mounts", encoding="utf-8") as mounts:
+            for line in mounts:
+                parts = line.split()
+                if len(parts) < 3:
+                    continue
+                mount_point = parts[1].replace("\\040", " ")
+                mount_real = os.path.realpath(mount_point)
+                if not mount_real:
+                    continue
+                if (
+                    current_path == mount_real
+                    or current_path.startswith(mount_real.rstrip("/") + "/")
+                ) and len(mount_real) > best_match_len:
+                    best_match_len = len(mount_real)
+                    best_fs_type = parts[2].lower()
+        if best_fs_type:
+            return best_fs_type in fs_targets
+    except OSError:
+        pass
+
+    return False
+
+
 # Type alias for summary dictionaries
 Summary = dict[str, Any]
 
@@ -321,8 +366,6 @@ def main(argv: list[str] | None = None) -> None:
 
     # Pass-through --help / --version to behave
     if any(flag in remaining for flag in ("-h", "--help", "--version")):
-        import subprocess
-
         code = subprocess.run(
             [sys.executable, "-m", "behave", *other_args, *feature_args]
         ).returncode
@@ -348,6 +391,7 @@ def main(argv: list[str] | None = None) -> None:
         or coverage_mode
         or len(feature_paths) == 1
         or len(feature_paths) <= 2
+        or _is_btrfs_or_overlayfs()
     ):
         # ---- sequential in-process mode ----
         _, total = _run_features_inprocess(feature_paths, other_args)