Docker Volume : Unexpected Owner on Windows

I’m trying to understand how the Ownership of Volumes works on Windows for Docker Container.

I’m using the following Dockerfile as a test

FROM centos:7
MAINTAINER Lovely Sausage
RUN echo "root:root" | chpasswd

# DUMMY MYSQL
RUN 
   adduser mysql && 
   mkdir -p /mysql

# DUMMY POSTGRESQL
RUN 
   adduser postgres && 
   mkdir -p /postgresql

When I run it using the following command

docker run -d -v //c/mysql:/mysql -v //c/postgresql:/postgresql --name centos7_vol1 centos7_vol

I can see that the folders have ownership as follows

drwxrwxrwx 1 mysql ftp 0 Nov 21 11:43 mysql
drwxrwxrwx 1 mysql ftp 0 Nov 21 11:43 postgresql

I don’t understand why especially because if I change the Dockerfile so that the DUMMY POSTGRESQL part comes before the DUMMY MYSQL part then the ownership is as follows

drwxrwxrwx 1 postgres ftp 0 Nov 21 11:43 mysql
drwxrwxrwx 1 postgres ftp 0 Nov 21 11:43 postgresql

Where are these permissions being set?

Source: StackOverflow