diff --git a/pkg/api/event_handlers.go b/pkg/api/event_handlers.go
index f34914d3..ec27d60a 100644
--- a/pkg/api/event_handlers.go
+++ b/pkg/api/event_handlers.go
@@ -595,6 +595,7 @@ func emulatedTreeToTrace(ctx context.Context, resolver core.LibraryResolver, con
 					Token1: *t1,
 				}
 			}
+			// TODO: find out masters of t0, t1
 		}
 	}
 	return t, nil
diff --git a/pkg/core/trace.go b/pkg/core/trace.go
index bbadfed5..633b8774 100644
--- a/pkg/core/trace.go
+++ b/pkg/core/trace.go
@@ -101,6 +101,13 @@ func CollectAdditionalInfo(ctx context.Context, infoSource InformationSource, tr
 	var basicNftSale []tongo.AccountID
 	var stonfiPoolIDs []tongo.AccountID
 	visit(trace, func(trace *Trace) {
+		// when we emulate a trace,
+		// we construct "trace.AdditionalInfo" in emulatedTreeToTrace for all accounts the trace touches.
+		// moreover, some accounts change their states and some of them are not exist in the blockchain,
+		// so we must not inspect them again.
+		if trace.AdditionalInfo != nil {
+			return
+		}
 		if isDestinationJettonWallet(trace.InMsg) {
 			jettonWallets = append(jettonWallets, *trace.InMsg.Destination)
 		}
@@ -135,6 +142,13 @@ func CollectAdditionalInfo(ctx context.Context, infoSource InformationSource, tr
 		return err
 	}
 	visit(trace, func(trace *Trace) {
+		// when we emulate a trace,
+		// we construct "trace.AdditionalInfo" in emulatedTreeToTrace for all accounts the trace touches.
+		// moreover, some accounts change their states and some of them are not exist in the blockchain,
+		// so we must not inspect them again.
+		if trace.AdditionalInfo != nil {
+			return
+		}
 		trace.AdditionalInfo = &TraceAdditionalInfo{}
 		if isDestinationJettonWallet(trace.InMsg) {
 			if master, ok := masters[*trace.InMsg.Destination]; ok {