diff --git a/vowpalwabbit/fb_parser/src/parse_example_flatbuffer.cc b/vowpalwabbit/fb_parser/src/parse_example_flatbuffer.cc
index 8bc7db22bdf..966377505f9 100644
--- a/vowpalwabbit/fb_parser/src/parse_example_flatbuffer.cc
+++ b/vowpalwabbit/fb_parser/src/parse_example_flatbuffer.cc
@@ -373,30 +373,11 @@ int parser::get_namespace_index(const Namespace* ns, namespace_index& ni, VW::ex
     ni = static_cast<uint8_t>(ns->name()->c_str()[0]);
     return VW::experimental::error_code::success;
   }
-  else if (flatbuffers::IsFieldPresent(ns, Namespace::VT_HASH))
+  else
   {
     ni = ns->hash();
     return VW::experimental::error_code::success;
   }
-
-  if (_active_collection && _active_multi_ex)
-  {
-    RETURN_ERROR_LS(status, fb_parser_name_hash_missing)
-        << "Either name or hash field must be specified to get the namespace index in collection item with example "
-           "index "
-        << _example_index << "and multi example index " << _multi_ex_index;
-  }
-  else if (_active_multi_ex)
-  {
-    RETURN_ERROR_LS(status, fb_parser_name_hash_missing)
-        << "Either name or hash field must be specified to get the namespace index in multi example index "
-        << _multi_ex_index;
-  }
-  else
-  {
-    RETURN_ERROR_LS(status, fb_parser_name_hash_missing)
-        << "Either name or hash field must be specified to get the namespace index";
-  }
 }
 
 bool get_namespace_hash(VW::workspace* all, const Namespace* ns, uint64_t& hash)
diff --git a/vowpalwabbit/fb_parser/tests/example_data_generator.h b/vowpalwabbit/fb_parser/tests/example_data_generator.h
index 69a7805d1c8..6b12f9636fe 100644
--- a/vowpalwabbit/fb_parser/tests/example_data_generator.h
+++ b/vowpalwabbit/fb_parser/tests/example_data_generator.h
@@ -32,6 +32,10 @@ class example_data_generator
 
   static VW::rand_state create_test_random_state();
 
+  inline bool random_bool() { return rng.get_and_update_random() >= 0.5; }
+
+  inline int random_int(int min, int max) { return static_cast<int>(rng.get_and_update_random() * (max - min) + min); }
+
   prototype_namespace_t create_namespace(std::string name, uint8_t numeric_features, uint8_t string_features);
 
   prototype_example_t create_simple_example(uint8_t numeric_features, uint8_t string_features);
diff --git a/vowpalwabbit/fb_parser/tests/read_span_tests.cc b/vowpalwabbit/fb_parser/tests/read_span_tests.cc
index 5622be90dae..cac108a85e9 100644
--- a/vowpalwabbit/fb_parser/tests/read_span_tests.cc
+++ b/vowpalwabbit/fb_parser/tests/read_span_tests.cc
@@ -67,7 +67,7 @@ inline void verify_multi_ex(
 }  // namespace vwtest
 
 template <typename T, typename FB_t = typename vwtest::fb_type<T>::type>
-void create_flatbuffer_span_and_validate(VW::workspace& w, const T& prototype)
+void create_flatbuffer_span_and_validate(VW::workspace& w, vwtest::example_data_generator& data_gen, const T& prototype)
 {
   // This is what we expect to see when we use read_span_flatbuffer, since this is intended
   // to be used for inference, and we would prefer not to force consumers of the API to have
@@ -85,6 +85,11 @@ void create_flatbuffer_span_and_validate(VW::workspace& w, const T& prototype)
   flatbuffers::uoffset_t size = builder.GetSize();
 
   VW::multi_ex parsed_examples;
+  if (data_gen.random_bool())
+  {
+    parsed_examples.push_back(&ex_fac());
+  }
+
   VW::parsers::flatbuffer::read_span_flatbuffer(&w, buffer, size, ex_fac, parsed_examples);
 
   verify_multi_ex(w, prototype, parsed_examples);
@@ -100,7 +105,7 @@ TEST(FlatbufferParser, ReadSpanFlatbuffer_SingleExample)
   vwtest::prototype_example_t prototype = {
       {data_gen.create_namespace("A", 3, 4), data_gen.create_namespace("B", 2, 5)}, vwtest::simple_label(1.0f)};
 
-  create_flatbuffer_span_and_validate(*all, prototype);
+  create_flatbuffer_span_and_validate(*all, data_gen, prototype);
 }
 
 TEST(FlatbufferParser, ReadSpanFlatbuffer_MultiExample)
@@ -110,7 +115,7 @@ TEST(FlatbufferParser, ReadSpanFlatbuffer_MultiExample)
   vwtest::example_data_generator data_gen;
   vwtest::prototype_multiexample_t prototype = data_gen.create_cb_adf_example(3, 1, "tag");
 
-  create_flatbuffer_span_and_validate(*all, prototype);
+  create_flatbuffer_span_and_validate(*all, data_gen, prototype);
 }
 
 TEST(FlatbufferParser, ReadSpanFlatbuffer_ExampleCollectionSinglelines)
@@ -120,7 +125,7 @@ TEST(FlatbufferParser, ReadSpanFlatbuffer_ExampleCollectionSinglelines)
   vwtest::example_data_generator data_gen;
   vwtest::prototype_example_collection_t prototype = data_gen.create_simple_log(3, 3, 4);
 
-  create_flatbuffer_span_and_validate(*all, prototype);
+  create_flatbuffer_span_and_validate(*all, data_gen, prototype);
 }
 
 TEST(FlatbufferParser, ReadSpanFlatbuffer_ExampleCollectionMultiline)
@@ -130,13 +135,19 @@ TEST(FlatbufferParser, ReadSpanFlatbuffer_ExampleCollectionMultiline)
   vwtest::example_data_generator data_gen;
   vwtest::prototype_example_collection_t prototype = data_gen.create_cb_adf_log(1, 3, 4);
 
-  create_flatbuffer_span_and_validate(*all, prototype);
+  create_flatbuffer_span_and_validate(*all, data_gen, prototype);
 }
 
 template <int error_code>
 void finish_flatbuffer_and_expect_error(FlatBufferBuilder& builder, Offset<fb::ExampleRoot> root, VW::workspace& w)
 {
   VW::example_factory_t ex_fac = [&w]() -> VW::example& { return VW::get_unused_example(&w); };
+  VW::example_sink_f ex_sink = [&w](VW::example& ex) { VW::finish_example(w, ex); };
+  if (vwtest::example_data_generator{}::random_bool())
+  {
+    // This is only valid because ex_fac is grabbing an example from the VW example pool
+    ex_sink = nullptr;
+  }
 
   builder.FinishSizePrefixed(root);
 
@@ -147,7 +158,7 @@ void finish_flatbuffer_and_expect_error(FlatBufferBuilder& builder, Offset<fb::E
 
   VW::multi_ex parsed_examples;
   EXPECT_EQ(VW::parsers::flatbuffer::read_span_flatbuffer(
-                &w, buffer_copy.data(), buffer_copy.size(), ex_fac, parsed_examples),
+                &w, buffer_copy.data(), buffer_copy.size(), ex_fac, parsed_examples, ex_sink),
       error_code);
 }