diff --git a/include/bitcoin/system/stream/streamers/byte_reader.hpp b/include/bitcoin/system/stream/streamers/byte_reader.hpp
index 28c40436dc..3ddd639fe1 100644
--- a/include/bitcoin/system/stream/streamers/byte_reader.hpp
+++ b/include/bitcoin/system/stream/streamers/byte_reader.hpp
@@ -121,6 +121,7 @@ class byte_reader
     /// -----------------------------------------------------------------------
     /// cptr/raw overrides return nullptr if reader is or becomes invalid.
     /// Non-null raw return must be destroyed using reader's allocator/arena.
+    /// Null raw return implies invalidated stream.
 
     /// Read all remaining bytes to chunk.
     data_chunk read_bytes() NOEXCEPT override;
diff --git a/src/chain/operation.cpp b/src/chain/operation.cpp
index 6aafff8bf3..d2ac572f84 100644
--- a/src/chain/operation.cpp
+++ b/src/chain/operation.cpp
@@ -234,6 +234,8 @@ void operation::assign_data(reader& source) NOEXCEPT
     {
         code_ = any_invalid;
         source.set_position(start);
+
+        // An invalid source.read_bytes_raw returns nullptr.
         data_.reset(POINTER(data_chunk, allocator, source.read_bytes_raw()));
     }
 
diff --git a/src/chain/witness.cpp b/src/chain/witness.cpp
index 8880df19e6..feee8131a2 100644
--- a/src/chain/witness.cpp
+++ b/src/chain/witness.cpp
@@ -176,8 +176,12 @@ void witness::assign_data(reader& source, bool prefix) NOEXCEPT
 
         for (size_t element = 0; element < count; ++element)
         {
+            // If read_bytes_raw returns nullptr invalid source is implied.
             const auto size = source.read_size(max_block_weight);
             const auto bytes = source.read_bytes_raw(size);
+            if (is_null(bytes))
+                break;
+
             stack_.emplace_back(POINTER(data_chunk, allocator, bytes));
             size_ = element_size(size_, stack_.back());
         }
@@ -186,8 +190,12 @@ void witness::assign_data(reader& source, bool prefix) NOEXCEPT
     {
         while (!source.is_exhausted())
         {
+            // If read_bytes_raw returns nullptr invalid source is implied.
             const auto size = source.read_size(max_block_weight);
             const auto bytes = source.read_bytes_raw(size);
+            if (is_null(bytes))
+                break;
+
             stack_.emplace_back(POINTER(data_chunk, allocator, bytes));
             size_ = element_size(size_, stack_.back());
         }