diff --git a/lib/py/src/ext/protocol.tcc b/lib/py/src/ext/protocol.tcc
index 03cfc9b..aad5a3c 100644
--- a/lib/py/src/ext/protocol.tcc
+++ b/lib/py/src/ext/protocol.tcc
@@ -705,7 +705,7 @@
       return nullptr;
     }
     if (isUtf8(typeargs)) {
-      return PyUnicode_DecodeUTF8(buf, len, 0);
+      return PyUnicode_DecodeUTF8(buf, len, "replace");
     } else {
       return PyBytes_FromStringAndSize(buf, len);
     }