distinct not work properly in some cases for spider tables

SET @@session.spider_same_server_link = ON; 

GRANT ALL PRIVILEGES ON *.* TO 'spinne'@'127.0.0.1'  IDENTIFIED BY 'Widow2021!';

CREATE SERVER data1

FOREIGN DATA WRAPPER mysql

OPTIONS(

HOST '127.0.0.1',

DATABASE 'test',

USER 'spinne',

PASSWORD 'Widow2021!'

); 

CREATE TABLE IF NOT EXISTS `spider_tab` (

  `col1` varchar(10) NOT NULL,

  `col2` varchar(10) NOT NULL,

  PRIMARY KEY (`col1`,`col2`)

) ENGINE=SPIDER DEFAULT CHARSET=utf8 COMMENT='wrapper "mariadb", table "spider_data_tab"'

PARTITION BY LIST COLUMNS(`col2`)

(PARTITION `pt1` DEFAULT COMMENT = 'srv "data1"' ENGINE = SPIDER);

CREATE TABLE IF NOT EXISTS `spider_data_tab` (

  `col1` varchar(10) NOT NULL,

  `col2` varchar(10) NOT NULL,

  `col3` datetime NOT NULL DEFAULT '0001-01-01 00:00:00',

  PRIMARY KEY (`col1`,`col2`, `col3`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8 ROW_FORMAT=COMPRESSED KEY_BLOCK_SIZE=8

 PARTITION BY RANGE  COLUMNS(`col3`)

(PARTITION `pmax` VALUES LESS THAN (MAXVALUE) ENGINE = InnoDB);

insert into `spider_data_tab` VALUES

("aaaaaaaaa","00100","2020-05-05 00:00:00")

,("bbbbbbbbb","00999","2020-05-06 00:00:00")

,("bbbbbbbbb","00100","2020-05-06 00:00:00")

,("ccccccccc","00999","2020-05-06 00:00:00")

,("ddddddddd","00999","2020-05-06 00:00:00")

,("eeeeeeeee","00999","2020-05-06 00:00:00")

,("fffffffff","00999","2020-05-06 00:00:00")

,("ggggggggg","00999","2020-05-06 00:00:00")

,("hhhhhhhhh","00999","2020-05-06 00:00:00");

 SELECT distinct col2 FROM spider_tab WHERE col2="00999";

SELECT distinct col2 FROM spider_data_tab WHERE col2="00999";