diff --git a/src/transaction/transaction.rs b/src/transaction/transaction.rs
index b30ef6e..9d20b00 100644
--- a/src/transaction/transaction.rs
+++ b/src/transaction/transaction.rs
@@ -1265,6 +1265,11 @@ struct Committer<PdC: PdClient = PdRpcClient> {
 }
 
 impl<PdC: PdClient> Committer<PdC> {
+    // CheckNotExists is checked in the prewrite phase and should not appear in the commit phase.
+    fn filter_out_check_not_exists_mutations(&mut self) {
+        self.mutations.retain(|m| m.op() != Op::CheckNotExists)
+    }
+
     async fn commit(mut self) -> Result<Option<Timestamp>> {
         debug!("committing");
 
@@ -1281,6 +1286,8 @@ impl<PdC: PdClient> Committer<PdC> {
             return Ok(min_commit_ts);
         }
 
+        self.filter_out_check_not_exists_mutations();
+
         let commit_ts = if self.options.async_commit {
             // FIXME: min_commit_ts == 0 => fallback to normal 2PC
             min_commit_ts.unwrap()