diff --git a/src/proto_alpha/lib_protocol/test/helpers/incremental.ml b/src/proto_alpha/lib_protocol/test/helpers/incremental.ml
index b6153dd85..ebd9e619c 100644
--- a/src/proto_alpha/lib_protocol/test/helpers/incremental.ml
+++ b/src/proto_alpha/lib_protocol/test/helpers/incremental.ml
@@ -164,6 +164,7 @@ let finalize_block st =
     { st.header with
       shell = {
         st.header.shell with
+        level = Int32.succ st.header.shell.level ;
         operations_hash ; fitness = result.fitness ;
       } } in
   let hash = Block_header.hash header in