diff --git a/src/streamsync/core.py b/src/streamsync/core.py
index eb52317c..7ca6ebdf 100644
--- a/src/streamsync/core.py
+++ b/src/streamsync/core.py
@@ -231,8 +231,28 @@ def remove(self, key) -> None:
     def _apply_raw(self, key) -> None:
         self.mutated.add(key)
 
-    def apply(self, key) -> None:
-        self._apply_raw(f"+{key}")
+    def apply_mutation_marker(self, key: Optional[str] = None, recursive: bool = False) -> None:
+        """
+        Adds the mutation marker to a state. The mutation marker is used to track changes in the state.
+
+        >>> self.apply_mutation_marker()
+
+        Add the mutation marker on a specific field
+
+        >>> self.apply_mutation_marker("field")
+
+        Add the mutation marker to a state and all of its children
+
+        >>> self.apply_mutation_marker(recursive=True)
+        """
+        keys = [key] if key is not None else self.state.keys()
+
+        for k in keys:
+            self._apply_raw(f"+{k}")
+            if recursive is True:
+                value = self.state[k]
+                if isinstance(value, StateProxy):
+                    value.apply_mutation_marker(recursive=True)
 
     @staticmethod
     def escape_key(key):
@@ -253,7 +273,7 @@ def carry_mutation_flag(base_key, child_key):
             serialised_value = None
 
             if isinstance(value, StateProxy):
-                if value.initial_assignment:
+                if f"+{key}" in self.mutated:
                     serialised_mutations[f"+{escaped_key}"] = serialised_value
                 value.initial_assignment = False
                 child_mutations = value.get_mutations_as_dict()
@@ -430,6 +450,9 @@ def _set_state_item(self, key: str, value: Any):
             state.ingest(value)
             self._state_proxy[key] = state._state_proxy
         else:
+            if isinstance(value, StateProxy):
+                value.apply_mutation_marker(recursive=True)
+
             self._state_proxy[key] = value
 
 
diff --git a/tests/test_core.py b/tests/test_core.py
index 6dcad4da..12b8b660 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -107,7 +107,7 @@ def test_mutations(self) -> None:
         assert d.get("features").get("height") == "short"
         assert d.get("state.with.dots").get("photo.jpeg") == "Corrupted"
 
-        self.sp.apply("age")
+        self.sp.apply_mutation_marker("age")
         m = self.sp.get_mutations_as_dict()
 
         assert m.get("+age") == 2
@@ -169,16 +169,31 @@ def test_replace_dictionary_content_in_a_state_with_schema_should_transform_it_i
         """
         Tests that replacing a dictionary content in a State without schema trigger mutations on all the children.
 
+        This processing must work after initialization and after recovering the mutations the first time.
+
         >>> _state = State({'items': {}})
         >>> _state["items"] = {k: v for k, v in _state["items"].items() if k != "Apple"}
         """
-
         _state = State({"items": {
             "Apple": {"name": "Apple", "type": "fruit"},
             "Cucumber": {"name": "Cucumber", "type": "vegetable"},
             "Lettuce": {"name": "Lettuce", "type": "vegetable"}
         }})
 
+        m = _state._state_proxy.get_mutations_as_dict()
+        assert m == {
+            '+items': None,
+            '+items.Apple': None,
+            '+items.Apple.name': "Apple",
+            '+items.Apple.type': "fruit",
+            '+items.Cucumber': None,
+            '+items.Cucumber.name': 'Cucumber',
+            '+items.Cucumber.type': 'vegetable',
+            '+items.Lettuce': None,
+            '+items.Lettuce.name': 'Lettuce',
+            '+items.Lettuce.type': 'vegetable'
+        }
+
         # When
         items = _state['items']
         items = {k: v for k, v in items.items() if k != "Apple"}