I wrote a simple mysql service

docker-compose.yml

version: '3'
 services:
 mysql:
 image: mysql:5.7
 volumes:
 - ./mysql/data:/var/lib/mysql
 - ./mysql/my.cnf:/etc/mysql/conf.d/my.cnf
 ports:
 - 3306:3306
 environment:
 - MYSQL_ROOT_PASSWORD=STi7hXedIfgdjxnRgJ

However, the my.cnf of the current directory cannot be read, which is very strange. this configuration was possible some time ago.
I tried it on linux and it was ok (I changed the port to 3307 in my.cnf)
On Linux:

Win

PS: SHARE disk also got

my.cnf

[mysqld]
 port=3307
 explicit_defaults_for_timestamp=1
 max_allowed_packet = 20M
 innodb_buffer_pool_size=200M
 server-id=344