FederatedX error 10000 on UPDATE

INSTALL SONAME 'ha_federatedx';

eval CREATE SERVER fedlink FOREIGN DATA WRAPPER mysql OPTIONS (USER 'root', HOST '127.0.0.1', DATABASE 'test1', PORT $MASTER_MYPORT);

create database test1;

create table test1.t1 (a int, b int);

create table test1.t2 (a int, b int);

CREATE TABLE t1 ENGINE=FEDERATED  connection='fedlink/t1';

CREATE TABLE t2 ENGINE=FEDERATED  connection='fedlink/t2';

set global federated_pushdown=1;

insert into t1 values (1,1),(2,2);

insert into t2 values (1,1),(2,2),(3,3);

update t1,t2 set t1.a=5 where t1.a=t2.a;

DROP TABLE t1,t2,test1.t1,test1.t2;

UNINSTALL SONAME 'ha_federatedx';