Missing files from host directory when syn folders between host and guest OS

[Sorcerer Stone]

Hello All,
My OS is Win10 pro with HyperV disabled. My build environment is Win10, Vagrant, VirtualBox (and Ubuntu Guest OS). I am testing an open source docker project from Github. In my vagrantfile, I have configured to mount a directory in my host OS (where all my docker-compose.yml, .env, other resources) are located. That statement is something like this:

config.vm.synced_folder "../thisproject", "/vagrant/thisproject", create:"true", type:"virtualbox"

After I ran the vagrantfile, I ssh into Ubuntu and navigated to the thisproject folder. All the files/sub-directories in my host OS are in the guest OS directory except the .env file. Actually when I unzipped the github project, the root directory for this project has a couple of other files .dockerignore, .gitignore. These files exist in my host OS directory, but not in the corresponding guest OS directory. All these missing files have something in common. Unlike other files, there is no alphanumeric characters before the "." For example, .env file. Of all these missing file, the one I am concorn about is the missing .env
 
Can someone please inform me why .env file failed to copy over? Or inside the VM, Ubuntu hide files with unusal names such as .env

Thanks in advance.

[Sorcerer Stone]

Sorry people. I exited and SSH back in. I saw all the files that I didn't see before. It has been copied over correctly.

Deeply apologize for the mis-information I posted earlier.