diff --git a/ethreceipts/ethreceipts.go b/ethreceipts/ethreceipts.go
index bcf71d1..34a8b42 100644
--- a/ethreceipts/ethreceipts.go
+++ b/ethreceipts/ethreceipts.go
@@ -754,7 +754,8 @@ func (l *ReceiptsListener) getMaxWaitBlocks(maxWait *int) uint64 {
 }
 
 func (l *ReceiptsListener) isBlockFinal(blockNum *big.Int) bool {
-	if l == nil || l.latestBlockNum() == nil || blockNum == nil {
+	latestBlockNum := l.latestBlockNum()
+	if latestBlockNum == nil || blockNum == nil {
 		return false
 	}
 	diff := big.NewInt(0).Sub(l.latestBlockNum(), blockNum)