diff --git a/pkg/tbtcpg/internal/test/marshaling.go b/pkg/tbtcpg/internal/test/marshaling.go
index 2dd72dbaa0..5a1d172ee0 100644
--- a/pkg/tbtcpg/internal/test/marshaling.go
+++ b/pkg/tbtcpg/internal/test/marshaling.go
@@ -273,7 +273,7 @@ func (psts *ProposeSweepTestScenario) UnmarshalJSON(data []byte) error {
 
 	// Unmarshal expected error
 	if len(unmarshaled.ExpectedErr) > 0 {
-		psts.ExpectedErr = fmt.Errorf(unmarshaled.ExpectedErr)
+		psts.ExpectedErr = fmt.Errorf("%s", unmarshaled.ExpectedErr)
 	}
 
 	return nil