diff --git a/comfy_execution/caching.py b/comfy_execution/caching.py
index 78212bde3..53d8e5bdb 100644
--- a/comfy_execution/caching.py
+++ b/comfy_execution/caching.py
@@ -51,17 +51,48 @@ class Unhashable:
     def __init__(self):
         self.value = float("NaN")
 
-def to_hashable(obj):
-    # So that we don't infinitely recurse since frozenset and tuples
-    # are Sequences.
-    if isinstance(obj, (int, float, str, bool, bytes, type(None))):
+
+def _sanitize_signature_input(obj, depth=0, max_depth=32):
+    if depth >= max_depth:
+        return Unhashable()
+
+    obj_type = type(obj)
+    if obj_type in (int, float, str, bool, bytes, type(None)):
         return obj
-    elif isinstance(obj, Mapping):
-        return frozenset([(to_hashable(k), to_hashable(v)) for k, v in sorted(obj.items())])
-    elif isinstance(obj, Sequence):
-        return frozenset(zip(itertools.count(), [to_hashable(i) for i in obj]))
+    elif obj_type is dict:
+        sanitized = []
+        for key in sorted(obj.keys(), key=lambda x: (type(x).__module__, type(x).__qualname__, repr(x))):
+            sanitized.append((_sanitize_signature_input(key, depth + 1, max_depth),
+                              _sanitize_signature_input(obj[key], depth + 1, max_depth)))
+        return tuple(sanitized)
+    elif obj_type in (list, tuple):
+        return tuple(_sanitize_signature_input(item, depth + 1, max_depth) for item in obj)
+    elif obj_type in (set, frozenset):
+        sanitized_items = [_sanitize_signature_input(item, depth + 1, max_depth) for item in obj]
+        sanitized_items.sort(key=repr)
+        return tuple(sanitized_items)
+    else:
+        # Execution-cache signatures should be built from prompt-safe values.
+        # If a custom node injects a runtime object here, mark it unhashable so
+        # the node won't reuse stale cache entries across runs, but do not walk
+        # the foreign object and risk crashing on custom container semantics.
+        return Unhashable()
+
+def to_hashable(obj):
+    # Restrict recursion to plain built-in containers. Some custom nodes insert
+    # runtime objects into prompt inputs for dynamic graph paths; walking those
+    # objects as generic Mappings / Sequences is unsafe and can destabilize the
+    # cache signature builder.
+    obj_type = type(obj)
+    if obj_type in (int, float, str, bool, bytes, type(None)):
+        return obj
+    elif obj_type is dict:
+        return frozenset([(to_hashable(k), to_hashable(v)) for k, v in sorted(obj.items(), key=lambda kv: repr(kv[0]))])
+    elif obj_type in (list, tuple):
+        return frozenset(zip(itertools.count(), [to_hashable(i) for i in obj]))
+    elif obj_type in (set, frozenset):
+        return frozenset([to_hashable(i) for i in obj])
     else:
-        # TODO - Support other objects like tensors?
         return Unhashable()
 
 class CacheKeySetID(CacheKeySet):
@@ -123,7 +154,7 @@ class CacheKeySetInputSignature(CacheKeySet):
                 ancestor_index = ancestor_order_mapping[ancestor_id]
                 signature.append((key,("ANCESTOR", ancestor_index, ancestor_socket)))
             else:
-                signature.append((key, inputs[key]))
+                signature.append((key, _sanitize_signature_input(inputs[key])))
         return signature
 
     # This function returns a list of all ancestors of the given node. The order of the list is
diff --git a/comfy_execution/graph_utils.py b/comfy_execution/graph_utils.py
index 496d2c634..75e4bc522 100644
--- a/comfy_execution/graph_utils.py
+++ b/comfy_execution/graph_utils.py
@@ -1,11 +1,16 @@
 def is_link(obj):
-    if not isinstance(obj, list):
+    # Prompt links produced by the frontend / GraphBuilder are plain Python
+    # lists in the form [node_id, output_index]. Some custom-node paths can
+    # inject foreign runtime objects into prompt inputs during on-prompt graph
+    # rewriting or subgraph construction. Be strict here so cache signature
+    # building never tries to treat list-like proxy objects as links.
+    if type(obj) is not list:
         return False
     if len(obj) != 2:
         return False
-    if not isinstance(obj[0], str):
+    if type(obj[0]) is not str:
         return False
-    if not isinstance(obj[1], int) and not isinstance(obj[1], float):
+    if type(obj[1]) not in (int, float):
         return False
     return True