diff --git a/src/trace/implementations/merge_batcher.rs b/src/trace/implementations/merge_batcher.rs
index 3d994013e..0a78a48cf 100644
--- a/src/trace/implementations/merge_batcher.rs
+++ b/src/trace/implementations/merge_batcher.rs
@@ -328,10 +328,6 @@ impl<
                     self.recycle(block);
                 } else {
                     // Keep the entire block.
-
-                    for (_, t, _) in block.iter() {
-                        frontier.insert_ref(t);
-                    }
                     if !keep.is_empty() {
                         keep_list.push((std::mem::take(&mut keep_frontier), std::mem::replace(&mut keep, self.empty())));
                     }