Cann't learn mac binding for a external ip with a snat rule. about ovn HOT 1 OPEN

()[root@ovn-tool-0 /]# ovn-sbctl create mac_binding  datapath=675eac5c-b01b-4ea8-b425-03570cff0c7e logical_port=lrp-43215760-af0b-480b-8f7d-a6d80de4f8e2 ip="172.16.10.27" mac="fa\:16\:3e\:26\:3b\:a7"
7d135ef1-8750-4df9-937d-8c035df9b8aa
()[root@ovn-tool-0 /]#

diff --git a/northd/northd.c b/northd/northd.c
index 08c262532..6b4e7422a 100644
--- a/northd/northd.c
+++ b/northd/northd.c
@@ -7140,6 +7140,9 @@ build_lswitch_rport_arp_req_flows(struct ovn_port *op,
         }
     }

+    struct sset snat_ips_v4 = SSET_INITIALIZER(&snat_ips_v4);
+    struct sset snat_ips_v6 = SSET_INITIALIZER(&snat_ips_v6);
+
     for (size_t i = 0; i < op->od->nbr->n_nat; i++) {
         struct ovn_nat *nat_entry = &op->od->nat_entries[i];
         const struct nbrec_nat *nat = nat_entry->nb;
@@ -7149,7 +7152,17 @@ build_lswitch_rport_arp_req_flows(struct ovn_port *op,
         }

         if (!strcmp(nat->type, "snat")) {
-            continue;
+            if (nat_entry_is_v6(nat_entry)) {
+                if (sset_contains(&snat_ips_v6, nat->external_ip)) {
+                    continue;
+                }
+                sset_add(&snat_ips_v6, nat->external_ip);
+            } else {
+                if (sset_contains(&snat_ips_v4, nat->external_ip)) {
+                    continue;
+                }
+                sset_add(&snat_ips_v4, nat->external_ip);
+            }
         }