diff --git a/parlai/agents/fid/fid.py b/parlai/agents/fid/fid.py
index 28ef2638360..b0c5c1bf1a3 100644
--- a/parlai/agents/fid/fid.py
+++ b/parlai/agents/fid/fid.py
@@ -348,7 +348,13 @@ def __init__(self, opt: Opt, shared: TShared = None):
                 'GoldDocRetrieverFiDAgent only works with `rag_retriever_query` being `"full_history"`. '
                 f'Changing opt value for `rag_retriever_query`: `"{prev_sel}"` -> `"full_history"`'
             )
-
+        if not (
+            opt['dynamic_batching'] in [None, 'off']
+            and opt.get('eval_dynamic_batching') in [None, 'off']
+        ):
+            raise RuntimeError(
+                "For now dynamic batching doesn't work with ObservationEchoRetriever as it cleans up _saved_docs mapping after each batch act."
+            )
         super().__init__(opt, shared=shared)
 
     @abstractmethod
@@ -376,6 +382,15 @@ def _set_query_vec(self, observation: Message) -> Message:
         self.show_observation_to_echo_retriever(observation)
         super()._set_query_vec(observation)
 
+    def batch_act(self, observations):
+        """
+        Clear the _saved_docs and _query_ids mappings in ObservationEchoRetriever.
+        """
+        batch_reply = super().batch_act(observations)
+        if hasattr(self.model_api.retriever, 'clear_mapping'):
+            self.model_api.retriever.clear_mapping()
+        return batch_reply
+
 
 class WizIntGoldDocRetrieverFiDAgent(GoldDocRetrieverFiDAgent):
     """
diff --git a/parlai/agents/rag/retrievers.py b/parlai/agents/rag/retrievers.py
index f7d472612d1..5d15059847b 100644
--- a/parlai/agents/rag/retrievers.py
+++ b/parlai/agents/rag/retrievers.py
@@ -1332,7 +1332,7 @@ def tokenize_query(self, query: str) -> List[int]:
     def get_delimiter(self) -> str:
         return self._delimiter
 
-    def _clear_mapping(self):
+    def clear_mapping(self):
         self._query_ids = dict()
         self._saved_docs = dict()
         self._largest_seen_idx = -1
@@ -1354,9 +1354,6 @@ def retrieve_and_score(
             query.device
         )
 
-        # empty the 2 mappings after each retrieval
-        self._clear_mapping()
-
         return retrieved_docs, retrieved_doc_scores
 
 
@@ -1416,7 +1413,7 @@ def get_top_chunks(
         doc_url: str,
     ):
         """
-        Return chunks according to the woi_chunk_retrieved_docs_mutator
+        Return chunks according to the woi_chunk_retrieved_docs_mutator.
         """
         if isinstance(doc_chunks, list):
             docs = ''.join(doc_chunks)