diff --git a/src/OutputFile.h b/src/OutputFile.h
index ea62b1e4ed0f526f39dd275c65864499c90aa8fb..db4c13b355c14b88b5ab69b04ce37f57bf974be5 100644
--- a/src/OutputFile.h
+++ b/src/OutputFile.h
@@ -52,7 +52,10 @@ struct LumisectionMetadata {
       : max_index(max_index_per_ls) {}
 
   void UpdateIndex(uint32_t global_index) {
-    assert(lumisection == (global_index / (max_index + 1) + 1));
+    std::cout << "Lumisection = " << lumisection << ", index = " << index_in_lumisection
+              << std::endl;
+    std::cout << "New LS = " << (global_index / (max_index + 1) + 1) << ", global index = " << global_index << std::endl;
+    assert(lumisection == 0 || lumisection == (global_index / (max_index + 1) + 1));
     lumisection = global_index / (max_index + 1) + 1;
     index_in_lumisection = global_index % (max_index + 1);
   }