Is this bug in MySQL Server 5.7.14?

[Мих ТехСпец]

Hi
May I found bug in MySQL Server 5.7.14.?!

I execute this script
LOAD DATA LOCAL INFILE 'D:/CSV/gk.txt' INTO TABLE gk
FIELDS TERMINATED BY ',' ENCLOSED BY '"' LINES TERMINATED BY '\r\n'
IGNORE 1 LINES;

in MySQL Server 5.7.14 I got errors for two symbols inside gk.txt
1. texts with symbol '\'
2. texts with wrong symbol '�'
In both cases error is "Invalid utf8 character string:"

BUT, when I use MySQL 5.6.35 - I HAVE NOT any errors!!!

file gk.txt is UTF-8
DataBase charset/collation is utf8/utf8_general_ci


the table is
----
CREATE TABLE gk (
ben_text varchar(420) NOT NULL COMMENT 'Текст'
)
ENGINE = MYISAM
CHARACTER SET utf8
COLLATE utf8_general_ci;

Both MySQL Servers have some values for
----
SHOW VARIABLES LIKE 'character_set%';
SHOW VARIABLES LIKE 'collation%';
===
character_set_client utf8
character_set_connection utf8
character_set_database utf8
character_set_filesystem binary
character_set_results utf8
character_set_server latin1
character_set_system utf8
character_sets_dir c:\wamp\bin\mysql\mysqlX.X.XX\share\charsets\

collation_connection utf8_general_ci
collation_database utf8_general_ci
collation_server latin1_swedish_ci