diff --git a/evm/src/cross_table_lookup.rs b/evm/src/cross_table_lookup.rs
index ff6c2a3d..e80e5b29 100644
--- a/evm/src/cross_table_lookup.rs
+++ b/evm/src/cross_table_lookup.rs
@@ -585,6 +585,7 @@ pub(crate) fn verify_cross_table_lookups<
             );
         }
     }
+    debug_assert!(ctl_zs_openings.iter_mut().all(|iter| iter.next().is_none()));
 
     Ok(())
 }
@@ -646,4 +647,5 @@ pub(crate) fn verify_cross_table_lookups_circuit<
             }
         }
     }
+    debug_assert!(ctl_zs_openings.iter_mut().all(|iter| iter.next().is_none()));
 }