We are using Trellis and Vagrant to provision developer WordPress instances on windows machine (within the Windows Subsystem for Linux.) On one machine we are having a lot of issues, and have managed to figure out that the Vagrant::Util::Platform.platform variable is set to mingw32 on the machines that work well, but it is set to linux-gnu on the problematic machine.
Tracing back a bit further to https://github.com/hashicorp/vagrant/blob/master/lib/vagrant/util/platform.rb it appears that Vagrant uses RbConfig::CONFIG["host_os"] to determine the platform.
Not sure where to proceed from there - what would cause Ruby to report Linux in the WSL of one machine, but Windows on the WSL of another machine?