diff --git a/vllm/distributed/kv_transfer/kv_connector/v1/moriio/moriio_common.py b/vllm/distributed/kv_transfer/kv_connector/v1/moriio/moriio_common.py
index f73f5b2cdcdd..16bda11e8ae1 100644
--- a/vllm/distributed/kv_transfer/kv_connector/v1/moriio/moriio_common.py
+++ b/vllm/distributed/kv_transfer/kv_connector/v1/moriio/moriio_common.py
@@ -292,8 +292,14 @@ def add_new_req(
             remote_engine_id=kv_transfer_params["remote_engine_id"],
             remote_host=kv_transfer_params["remote_host"],
             remote_port=kv_transfer_params["remote_port"],
-            remote_handshake_port=kv_transfer_params["remote_handshake_port"],
-            remote_notify_port=kv_transfer_params["remote_notify_port"],
+            remote_handshake_port=kv_transfer_params.get(
+                "remote_handshake_port",
+                int(MoRIIOConstants.DEFAULT_HANDSHAKE_PORT),
+            ),
+            remote_notify_port=kv_transfer_params.get(
+                "remote_notify_port",
+                int(MoRIIOConstants.DEFAULT_NOTIFY_PORT),
+            ),
             tp_size=kv_transfer_params.get("tp_size", 1),
             remote_dp_size=kv_transfer_params.get("remote_dp_size", 1),
         )
diff --git a/vllm/distributed/kv_transfer/kv_connector/v1/moriio/moriio_connector.py b/vllm/distributed/kv_transfer/kv_connector/v1/moriio/moriio_connector.py
index 2494857c6c69..15cb7a9fd8b2 100644
--- a/vllm/distributed/kv_transfer/kv_connector/v1/moriio/moriio_connector.py
+++ b/vllm/distributed/kv_transfer/kv_connector/v1/moriio/moriio_connector.py
@@ -266,6 +266,13 @@ def __init__(self, vllm_config: VllmConfig, engine_id: str):
         self._reqs_need_recv: dict[ReqId, tuple[Request, list[int]]] = {}
         self._reqs_need_save: dict[ReqId, tuple[Request, list[int]]] = {}
 
+        # Snapshot of kv_transfer_params captured at allocation time.
+        # The Request object's kv_transfer_params may be mutated or
+        # cleared between scheduler steps, so we cache a copy here
+        # to ensure build_connector_meta has access to the original
+        # values (remote_block_ids, remote_engine_id, etc.).
+        self._req_kv_params: dict[ReqId, dict] = {}
+
         # For chunked prefill, we perform layer-wise access within the final chunk.
         # TODO: Perform transfer at end chunk.
         self._reqs_need_pending_save: dict[ReqId, tuple[Request, list[int]]] = {}
@@ -341,6 +348,7 @@ def update_state_after_alloc(
         if params.get("do_remote_decode"):
             local_block_ids = blocks.get_block_ids()[0]
             self._reqs_need_save[request.request_id] = (request, local_block_ids)
+            self._req_kv_params[request.request_id] = dict(params)
 
         if params is not None and params.get("do_remote_prefill"):
             if self.mode == MoRIIOMode.READ:
@@ -365,6 +373,9 @@ def update_state_after_alloc(
                             request,
                             local_block_ids,
                         )
+                        self._req_kv_params[request.request_id] = dict(
+                            params
+                        )
                     else:
                         logger.warning(
                             "Got invalid KVTransferParams: %s. This "
@@ -458,15 +469,19 @@ def build_connector_meta(
 
         # Loop through scheduled reqs and convert to ReqMeta.
         for req_id, (req, block_ids) in self._reqs_need_recv.items():
-            assert req.kv_transfer_params is not None
+            kv_params = self._req_kv_params.get(
+                req_id, req.kv_transfer_params or {}
+            )
             meta.add_new_req(
                 request_id=req_id,
                 local_block_ids=block_ids,
-                kv_transfer_params=req.kv_transfer_params,
+                kv_transfer_params=kv_params,
             )
 
         for req_id, (req, block_ids) in self._reqs_need_save.items():
-            assert req.kv_transfer_params is not None
+            kv_params = self._req_kv_params.get(
+                req_id, req.kv_transfer_params or {}
+            )
             if req.num_prompt_tokens > len(block_ids) * self.block_size:
                 # not last chunk prefill
                 self._reqs_need_pending_save[req_id] = (req, block_ids)
@@ -474,13 +489,17 @@ def build_connector_meta(
             meta.add_new_req(
                 request_id=req_id,
                 local_block_ids=block_ids,
-                kv_transfer_params=req.kv_transfer_params,
+                kv_transfer_params=kv_params,
                 write_mode=True,
             )
         # Clear the list once workers start the transfers
 
         meta.reqs_to_send = self._reqs_need_send
 
+        for req_id in self._reqs_need_recv:
+            self._req_kv_params.pop(req_id, None)
+        for req_id in self._reqs_need_save:
+            self._req_kv_params.pop(req_id, None)
         self._reqs_need_recv.clear()
         self._reqs_need_save.clear()
         self._reqs_need_send = {}
@@ -1086,7 +1105,17 @@ def register_kv_caches(self, kv_caches: dict[str, torch.Tensor]):
             self.slot_size_bytes = (
                 kv_elem_size * n_kv_heads * head_dim
             )  # 1 token 1 layer size , slot size
-        assert block_size == self.block_size
+        # The attention backend may override the configured block_size
+        # (e.g. FlashMLA forces block_size=64 for MLA models regardless
+        # of the --block-size CLI flag). Trust the actual tensor shape.
+        if block_size != self.block_size:
+            logger.info(
+                "KV cache block_size=%d differs from config block_size=%d; "
+                "using actual tensor shape (attention backend override).",
+                block_size,
+                self.block_size,
+            )
+            self.block_size = block_size
         # TODO(tms): self.block_len needs to be per-layer for sliding window,
         # hybrid attn, etc
         # block size in bytes