(1) USASCII data seems not affected
(2) Phenonemon seem when Japanese data are included
(3) I have not tested on non-Japanese UTF-8 data yet
(4) I confirmed that works correctly and no problem seen when InnoDB is selected
(5) I have not tested all string manipulation functions yet , for I cannot find the list of available functions supported in ColumnStore mode in the website
(6) Currently, avoid using functions, or not storing non-ASCII data when ColumnStore engine is selected

/* Test Code (Begin) */
CREATE DATABASE IF NOT EXISTS `mytest` DEFAULT CHARSET=utf8 DEFAULT COLLATE=utf8_general_ci ;
USE `mytest` ; COMMIT ;
CREATE TABLE `mytable` ( `col1` CHAR(99) , `col2` VARCHAR(99) ) Engine=ColumnStore DEFAULT CHARSET=utf8 ;
COMMIT ;
INSERT INTO `mytable` ( `col1` , `col2` ) VALUES ( 'Aaa' , 'Bbb' ) ;
INSERT INTO `mytable` ( `col1` , `col2` ) VALUES ( 'Ccc' , 'Ddd' ) ;
INSERT INTO `mytable` ( `col1` , `col2` ) VALUES ( ' A quick brown FOX ! ' , ' Jumped over the lazy DOG ? ' ) ;
INSERT INTO `mytable` ( `col1` , `col2` ) VALUES ( 'テスト' , 'ﾃｽﾄ' ) ;
INSERT INTO `mytable` ( `col1` , `col2` ) VALUES ( 'マリアの実験' , 'ＭａｒｉａＤＢ＿Ｔｅｓｔ' ) ;
INSERT INTO `mytable` ( `col1` , `col2` ) VALUES ( ' 半角空白囲み ' , '　全角空白囲み　' ) ;
COMMIT ;
SELECT `col1` , `col2` FROM `mytable` ; /* Trailing half-width whitespaces got lost ? */
SELECT `col1` , TRIM(`col1`) , `col2` , TRIM(`col2`) FROM `mytable` ; /* Internal Error */
SELECT `col1` , UPPER(`col1`) , `col2` , LOWER(`col2`) FROM `mytable` ; /* No error but incorrect result however the functions may not support full-width case conversion */
SELECT `col1` , LENGTH(`col1`) , `col2` , LENGTH(`col2`) FROM `mytable` ; /* Not char count, rather consumed bytes ? */
SELECT `col1` , REVERSE(`col1`) , `col2` , REVERSE(`col2`) FROM `mytable` ; /* Trailing blank lost in the result */
SELECT `col1` , SUBSTRING(`col1` , 2 , 2 ) , `col2` , SUBSTRING(`col2` , 2 , 2 ) FROM `mytable` ; /* No error but incorrect result */
COMMIT ;
DROP DATABASE IF EXISTS `mytest` ; COMMIT ;
USE `mysql` ; COMMIT ;
/* Test Code (End) */