Release remaining transport subscriptions at instance destruction

src/utun_instance.c

@@ -624,6 +624,23 @@ static void instance_destroy(struct UTUN_INSTANCE* instance, int owns_config) {
     DEBUG_INFO(DEBUG_CATEGORY_SYS, "[INSTANCE_DESTROY] Freeing instance memory");
 
     // Cleanup nodeinfo callback chain
+    while (instance->new_conn_cbks) {
+        struct etcp_inst_cbk_entry* entry = instance->new_conn_cbks;
+        instance->new_conn_cbks = entry->next; u_free(entry);
+    }
+    while (instance->link_status_cbks) {
+        struct etcp_link_status_cbk_entry* entry = instance->link_status_cbks;
+        instance->link_status_cbks = entry->next; u_free(entry);
+    }
+    while (instance->conn_status_cbks) {
+        struct etcp_status_cbk_entry* entry = instance->conn_status_cbks;
+        instance->conn_status_cbks = entry->next; u_free(entry);
+    }
+    while (instance->socket_cbks) {
+        struct etcp_socket_cbk_entry* entry = instance->socket_cbks;
+        instance->socket_cbks = entry->next; u_free(entry);
+    }
+    DEBUG_DEBUG(DEBUG_CATEGORY_SYS, "instance transport subscriptions released");
     while (instance->nodeinfo_cbks) {
         struct nodeinfo_cbk_entry* r = instance->nodeinfo_cbks;
         instance->nodeinfo_cbks = r->next; u_free(r);