diff --git a/pkg/services/oracle/oracle.go b/pkg/services/oracle/oracle.go
index 3df90edc3..58e9d4b89 100644
--- a/pkg/services/oracle/oracle.go
+++ b/pkg/services/oracle/oracle.go
@@ -171,7 +171,7 @@ func (o *Oracle) Run() {
 			return
 		case <-tick.C:
 			var reprocess []uint64
-			o.respMtx.RLock()
+			o.respMtx.Lock()
 			o.removed = make(map[uint64]bool)
 			for id, incTx := range o.responses {
 				incTx.RLock()