diff --git a/radix-engine/src/system/system_modules/execution_trace/module.rs b/radix-engine/src/system/system_modules/execution_trace/module.rs
index fd3bfeea48..c83b29b8de 100644
--- a/radix-engine/src/system/system_modules/execution_trace/module.rs
+++ b/radix-engine/src/system/system_modules/execution_trace/module.rs
@@ -91,8 +91,10 @@ impl From<&BucketSnapshot> for ResourceSpecifier {
 
 #[derive(Debug, Clone)]
 pub enum VaultOp {
-    Put(ResourceAddress, Decimal), // TODO: add non-fungible support
+    Put(ResourceAddress, Decimal),
     Take(ResourceAddress, Decimal),
+    // We deliberately ignore ids and use amount only for non-fungibles
+    // This is to keep backward-compatibility with users of the `ResourceChange` struct.
     TakeNonFungibles(ResourceAddress, Decimal),
     TakeAdvanced(ResourceAddress, Decimal),
     LockFee(Decimal, bool),