diff --git a/hathor/_openapi/openapi_base.json b/hathor/_openapi/openapi_base.json
index c24ab9786..9eec06b7f 100644
--- a/hathor/_openapi/openapi_base.json
+++ b/hathor/_openapi/openapi_base.json
@@ -7,7 +7,7 @@
         ],
 	"info": {
             "title": "Hathor API",
-            "version": "0.68.0"
+            "version": "0.68.1"
 	},
 	"consumes": [
             "application/json"
diff --git a/hathor/nanocontracts/exception.py b/hathor/nanocontracts/exception.py
index cfa467d9e..3c95bab5f 100644
--- a/hathor/nanocontracts/exception.py
+++ b/hathor/nanocontracts/exception.py
@@ -155,6 +155,11 @@ class NCForbiddenReentrancy(NCFail):
     pass
 
 
+class NCTypeError(NCFail):
+    """Raised when a wrong type is used."""
+    pass
+
+
 class UnknownFieldType(NCFail):
     """Raised when there is no field available for a given type."""
     pass
diff --git a/hathor/nanocontracts/resources/state.py b/hathor/nanocontracts/resources/state.py
index be2f401b5..08f242e94 100644
--- a/hathor/nanocontracts/resources/state.py
+++ b/hathor/nanocontracts/resources/state.py
@@ -203,6 +203,9 @@ def render_GET(self, request: 'Request') -> bytes:
             except KeyError:
                 fields[field] = NCValueErrorResponse(errmsg='field not found')
                 continue
+            except TypeError:
+                fields[field] = NCValueErrorResponse(errmsg='field cannot be rendered')
+                continue
 
             json_value = field_nc_type.value_to_json(value)
             fields[field] = NCValueSuccessResponse(value=json_value)
diff --git a/hathor/nanocontracts/runner/runner.py b/hathor/nanocontracts/runner/runner.py
index a04903320..c94699a07 100644
--- a/hathor/nanocontracts/runner/runner.py
+++ b/hathor/nanocontracts/runner/runner.py
@@ -40,6 +40,7 @@
     NCInvalidPublicMethodCallFromView,
     NCInvalidSyscall,
     NCMethodNotFound,
+    NCTypeError,
     NCUninitializedContractError,
     NCViewMethodError,
 )
@@ -1241,6 +1242,9 @@ def syscall_create_child_fee_token(
     @_forbid_syscall_from_view('emit_event')
     def syscall_emit_event(self, data: bytes) -> None:
         """Emit a custom event from a Nano Contract."""
+        if not isinstance(data, bytes):
+            raise NCTypeError(f'got {type(data)} instead of bytes')
+        data = bytes(data)  # force actual bytes because isinstance could be True for "compatible" types
         assert self._call_info is not None
         self._call_info.nc_logger.__emit_event__(data)
 
diff --git a/hathor/version.py b/hathor/version.py
index 1243b5377..6f9d4ea5a 100644
--- a/hathor/version.py
+++ b/hathor/version.py
@@ -19,7 +19,7 @@
 
 from structlog import get_logger
 
-BASE_VERSION = '0.68.0'
+BASE_VERSION = '0.68.1'
 
 DEFAULT_VERSION_SUFFIX = "local"
 BUILD_VERSION_FILE_PATH = "./BUILD_VERSION"
diff --git a/hathor_tests/nanocontracts/test_emit_event_payload.py b/hathor_tests/nanocontracts/test_emit_event_payload.py
new file mode 100644
index 000000000..bd7d1af2a
--- /dev/null
+++ b/hathor_tests/nanocontracts/test_emit_event_payload.py
@@ -0,0 +1,66 @@
+# Copyright 2025 Hathor Labs
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from hathor.manager import HathorManager
+from hathor.nanocontracts import NC_EXECUTION_FAIL_ID, Blueprint, Context, public
+from hathor.transaction import Block, Transaction
+from hathor.transaction.nc_execution_state import NCExecutionState
+from hathor_tests.dag_builder.builder import TestDAGBuilder
+from hathor_tests.nanocontracts.blueprints.unittest import BlueprintTestCase
+
+
+class EmitEventWithDictBlueprint(Blueprint):
+    @public
+    def initialize(self, ctx: Context) -> None:
+        # Intentionally emit a non-bytes payload; runtime type checks must reject this.
+        self.syscall.emit_event({'should': 'fail'})  # type: ignore[arg-type]
+
+
+class EmitEventPayloadTestCase(BlueprintTestCase):
+    def build_manager(self) -> HathorManager:
+        # Lower reward spend requirement to avoid reward-lock interference in this focused test.
+        settings = self._settings._replace(REWARD_SPEND_MIN_BLOCKS=1)
+        return self.create_peer(
+            'unittests',
+            nc_indexes=True,
+            wallet_index=True,
+            settings=settings,
+        )
+
+    def setUp(self) -> None:
+        super().setUp()
+        self.blueprint_id = self._register_blueprint_class(EmitEventWithDictBlueprint)
+        self.dag_builder = TestDAGBuilder.from_manager(self.manager)
+
+    def test_emit_event_requires_bytes_payload(self) -> None:
+        artifacts = self.dag_builder.build_from_str(f'''
+            blockchain genesis b[1..5]
+            b3 < dummy     # ensure enough confirmations to unlock rewards
+
+            tx1.nc_id = "{self.blueprint_id.hex()}"
+            tx1.nc_method = initialize()
+
+            tx1 < b4 < b5
+            tx1 <-- b4
+        ''')
+
+        b4 = artifacts.get_typed_vertex('b4', Block)
+        tx1 = artifacts.get_typed_vertex('tx1', Transaction)
+
+        # Executing the contract must fail because emit_event payload is not bytes.
+        artifacts.propagate_with(self.manager, up_to='b4')
+        meta = tx1.get_metadata()
+        assert meta.first_block == b4.hash
+        assert meta.nc_execution == NCExecutionState.FAILURE
+        assert meta.voided_by == {NC_EXECUTION_FAIL_ID, tx1.hash}
diff --git a/hathor_tests/resources/nanocontracts/test_state.py b/hathor_tests/resources/nanocontracts/test_state.py
index 987208617..3db6b7c70 100644
--- a/hathor_tests/resources/nanocontracts/test_state.py
+++ b/hathor_tests/resources/nanocontracts/test_state.py
@@ -54,6 +54,8 @@ class MyBlueprint(Blueprint):
     address_details: dict[Address, dict[str, Amount]]
     bytes_field: bytes
     dict_with_bytes: dict[bytes, str]
+    list_field: list[int]
+    set_field: set[int]
     last_caller_id: CallerId
     last_bet_address: Address
     last_vertex_id: VertexId
@@ -67,6 +69,8 @@ def initialize(self, ctx: Context, token_uid: TokenUid, date_last_bet: Timestamp
         self.address_details = {}
         self.bytes_field = b''
         self.dict_with_bytes = {}
+        self.list_field = []
+        self.set_field = set()
         self.last_caller_id = ctx.caller_id
         self.last_bet_address = Address(b'\00' * 25)
         self.last_vertex_id = VertexId(ctx.vertex.hash)
@@ -214,6 +218,52 @@ def _fill_nc(
         sign_openssl(nano_header, private_key)
         self.manager.cpu_mining_service.resolve(nc)
 
+    @inlineCallbacks
+    def test_container_field_returns_field_error(self):
+        parents = [tx.hash for tx in self.genesis_txs]
+        timestamp = 1 + max(tx.timestamp for tx in self.genesis)
+
+        nc = Transaction(
+            weight=1,
+            inputs=[],
+            outputs=[],
+            parents=parents,
+            storage=self.tx_storage,
+            timestamp=timestamp
+        )
+        self._fill_nc(
+            nc,
+            self.bet_id,
+            'initialize',
+            [settings.HATHOR_TOKEN_UID, timestamp],
+            self.genesis_private_key,
+        )
+        self.assertTrue(self.manager.on_new_tx(nc))
+        add_new_block(self.manager)
+
+        response = yield self.web.get(
+            'state', [
+                (b'id', nc.hash.hex().encode('ascii')),
+                (b'fields[]', b'token_uid'),
+                (b'fields[]', b'address_details'),
+                (b'fields[]', b'list_field'),
+                (b'fields[]', b'set_field'),
+            ]
+        )
+
+        data = response.json_value()
+        self.assertTrue(data['success'])
+        fields = data['fields']
+        self.assertEqual(fields['token_uid'], {'value': settings.HATHOR_TOKEN_UID.hex()})
+        self.assertEqual(fields['address_details'], {'errmsg': 'field cannot be rendered'})
+        # XXX: these are ideally the errors that make sense to return:
+        # self.assertEqual(fields['list_field'], {'errmsg': 'field cannot be rendered'})
+        # self.assertEqual(fields['set_field'], {'errmsg': 'field cannot be rendered'})
+        # XXX: however the current implementation quirks field these:
+        self.assertEqual(fields['list_field'], {'errmsg': 'field not found'})
+        self.assertEqual(fields['set_field'], {'errmsg': 'field not found'})
+        # XXX: it will change in the future along with a complete state-api implementation for container fields
+
     @inlineCallbacks
     def test_success(self):
         parents = [tx.hash for tx in self.genesis_txs]
diff --git a/pyproject.toml b/pyproject.toml
index 2055668cd..de9dd54aa 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -14,7 +14,7 @@
 
 [tool.poetry]
 name = "hathor"
-version = "0.68.0"
+version = "0.68.1"
 description = "Hathor Network full-node"
 authors = ["Hathor Team <contact@hathor.network>"]
 license = "Apache-2.0"