diff --git a/README.md b/README.md
index 6ac2cb3..4510707 100644
--- a/README.md
+++ b/README.md
@@ -11,18 +11,18 @@ and storage-agnostic.
 `requirements.txt`:
 
 ```
-envelope_crypto @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_crypto.git@v0.1.8
+envelope_crypto @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_crypto.git@v0.1.10
 ```
 
 Direct:
 
 ```bash
-pip install "envelope_crypto @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_crypto.git@v0.1.8"
+pip install "envelope_crypto @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_crypto.git@v0.1.10"
 ```
 
 Requires `cryptography` (pulled transitively).
 
-Drop the `@v0.1.8` suffix from the line above to install the latest unpinned.
+Drop the `@v0.1.10` suffix from the line above to install the latest unpinned.
 
 ## First-time setup
 
@@ -80,10 +80,12 @@ enc = crypto.encrypt_data({"ssn": "..."})      # -> {"secure": True, "iv": ...,
 plain = crypto.decrypt_data(enc)               # -> {"ssn": "..."}
 ```
 
-Dict keys must be `str`. `encrypt_data` raises `TypeError` on a non-str key (e.g. an
-int-keyed dict of Discord snowflakes) instead of silently stringifying it — the
-underlying JSON encoding has no other key type, so a coerced key would come back out
-of `decrypt_data` as a `str` and no longer match the original lookup key.
+Dict keys must be `str`, at any nesting depth (including a dict nested inside a list
+or tuple). `encrypt_data` raises `TypeError` on a non-str key anywhere in the payload
+(e.g. an int-keyed dict of Discord snowflakes, even nested a few levels down) instead
+of silently stringifying it — the underlying JSON encoding has no other key type, so a
+coerced key would come back out of `decrypt_data` as a `str` and no longer match the
+original lookup key.
 
 For whole records: `decrypt_record(crypto, doc)` decrypts every `{secure, iv, data}`
 field (nested up to `traversal_level`, default 2); `is_encrypted_record(doc)` reports
@@ -98,11 +100,11 @@ if is_encrypted_record(doc):
     doc = decrypt_record(crypto, doc)
 ```
 
-`is_encrypted_record` falls back to an unbounded-depth scan once `traversal_level` is
-exhausted, so it reliably reports `True` for a blob left behind by a shallower
+`is_encrypted_record` always falls back to an unbounded-depth scan whenever its bounded
+pass finds nothing, so it reliably reports `True` for a blob left behind by a shallower
 `decrypt_record`/`reencrypt` call — safe to use as a leftover-detecting audit after
-rotation, regardless of how deep the blob is nested, including inside a list or
-tuple at any depth.
+rotation, regardless of how deep the blob is nested (including inside a list or tuple
+at any depth) and regardless of which `traversal_level` you pass; it never false-negatives.
 
 Naming aliases (same objects): `EnvelopeCrypto` = `DocumentCrypto` = `RecordCrypto`
 = `PCICrypto` (deprecated legacy alias). `decrypt_record` = `decrypt_document` =
diff --git a/pyproject.toml b/pyproject.toml
index 4ec1b15..730ab9c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "envelope_crypto"
-version = "0.1.9"
+version = "0.1.10"
 description = "Envelope encryption (RSA-OAEP wrapped AES-256-GCM) for dict records — config-free, storage-agnostic, installable."
 requires-python = ">=3.10"
 dependencies = [
diff --git a/src/envelope_crypto/envelope_crypto.py b/src/envelope_crypto/envelope_crypto.py
index a189afd..be4d29c 100644
--- a/src/envelope_crypto/envelope_crypto.py
+++ b/src/envelope_crypto/envelope_crypto.py
@@ -94,6 +94,20 @@ def _has_encrypted_field(record: Any) -> bool:
     return False
 
 
+def _non_str_key_types(data: Any) -> List[str]:
+    """unbounded-depth scan collecting type names of non-str dict keys, incl. dicts nested inside list/tuple items"""
+    found: List[str] = []
+    if isinstance(data, dict):
+        for key, value in data.items():
+            if not isinstance(key, str):
+                found.append(type(key).__name__)
+            found.extend(_non_str_key_types(value))
+    elif isinstance(data, (list, tuple)):
+        for item in data:
+            found.extend(_non_str_key_types(item))
+    return found
+
+
 def _require_rsa(key) -> None:
     """raise ValueError unless key is an RSA public or private key"""
     if not isinstance(key, (rsa.RSAPublicKey, rsa.RSAPrivateKey)):
@@ -390,9 +404,10 @@ class EnvelopeCrypto:
     def encrypt_data(self, data: Union[Dict[str, Any], str]) -> Dict[str, str]:
         """encrypt a dict or string under the data key with a unique IV
 
-        dict keys must be str: json.dumps silently stringifies int/float/bool/None
-        keys (e.g. a snowflake-int-keyed dict), which would make decrypt_data return
-        a dict that no longer matches the original by key type or identity - a
+        dict keys must be str, at any nesting depth (including dicts nested inside
+        lists/tuples): json.dumps silently stringifies int/float/bool/None keys
+        (e.g. a snowflake-int-keyed dict), which would make decrypt_data return a
+        dict that no longer matches the original by key type or identity - a
         non-str key is rejected here instead, so the failure is loud at encrypt
         time rather than a silent lookup miss after decrypt.
         """
@@ -401,11 +416,11 @@ class EnvelopeCrypto:
         if not isinstance(data, (dict, str)):
             raise TypeError(f"encrypt_data expects a dict or str, got {type(data).__name__}")
         if isinstance(data, dict):
-            non_str_keys = [key for key in data if not isinstance(key, str)]
-            if non_str_keys:
+            non_str_key_types = _non_str_key_types(data)
+            if non_str_key_types:
                 raise TypeError(
-                    "encrypt_data requires str dict keys, got non-str key(s): "
-                    f"{[type(key).__name__ for key in non_str_keys]}"
+                    "encrypt_data requires str dict keys (at any nesting depth), got non-str "
+                    f"key(s): {non_str_key_types}"
                 )
 
         data_str = json.dumps(data) if isinstance(data, dict) else data
@@ -509,11 +524,18 @@ PCICrypto = EnvelopeCrypto  # deprecated legacy alias; remove after all systems
 
 
 def _is_encrypted_value(value: Any, traversal_level: int) -> bool:
-    """bounded-pass check of a single field value, walking list/tuple items too"""
+    """bounded-pass check of a single field value, walking list/tuple items too
+
+    falls back to the unbounded _has_encrypted_field scan once traversal_level is
+    exhausted, so this can never return False for a value that still contains a
+    blob at any depth
+    """
     if _is_blob(value):
         return True
     if isinstance(value, dict):
-        return traversal_level > 0 and is_encrypted_record(value, traversal_level - 1)
+        if traversal_level > 0:
+            return is_encrypted_record(value, traversal_level - 1)
+        return _has_encrypted_field(value)
     if isinstance(value, (list, tuple)):
         return any(_is_encrypted_value(item, traversal_level) for item in value)
     return False
@@ -523,16 +545,18 @@ def is_encrypted_record(record, traversal_level: int = 2) -> bool:
     """return whether a record has any encrypted ({secure, iv, data}) fields
 
     checks `record` itself (the file-storage pattern) as well as fields up to
-    `traversal_level` deep, then falls back to an unbounded-depth scan - safe to
-    use as a leftover-detecting post-rotation audit; never returns False for a
-    record that still contains a blob, at any depth, including one nested inside
-    a list or tuple at any depth (both passes walk list/tuple items, not just
-    dict values).
+    `traversal_level` deep, then always falls back to an unbounded-depth scan if
+    the bounded pass found nothing - safe to use as a leftover-detecting
+    post-rotation audit; never returns False for a record that still contains a
+    blob, at any depth (including one nested inside a list or tuple), for any
+    traversal_level value, odd or even (both passes walk list/tuple items, not
+    just dict values).
 
     Args:
         record: the record (or bare blob) to check.
-        traversal_level: bounded-pass nesting depth before the unbounded
-            fallback scan (default 2).
+        traversal_level: bounded-pass nesting depth tried before the unbounded
+            fallback scan runs (default 2); purely a fast-path - the fallback
+            always makes the final call when the bounded pass finds nothing.
 
     Returns:
         True if record or anything nested under it is an encrypted blob.
@@ -553,7 +577,6 @@ def is_encrypted_record(record, traversal_level: int = 2) -> bool:
         for value in record.values():
             if _is_encrypted_value(value, traversal_level - 1):
                 return True
-        return False
 
     return any(_has_encrypted_field(value) for value in record.values())