spider returns incorrect results for FOUND_ROWS() with SELECT SQL_CALC_FOUND_ROWS

create table t2 (c int);

create table t1 (c int) ENGINE=Spider

COMMENT='WRAPPER "mysql", srv "srv",TABLE "t2"';

insert into t1 values (1), (2), (3), (4), (5);

select SQL_CALC_FOUND_ROWS c from t1 order by c limit 4;

c

1

2

3

4

select found_rows();

found_rows()

1

select SQL_CALC_FOUND_ROWS c from t2 order by c limit 4;

c

1

2

3

4

select found_rows();

found_rows()

5