yarn run fails when stdin is redirected

[agross]

What is the current behavior?

Reproduction repo here: https://github.com/agross/yarn-run-windows

The repro runs a CLI installed by yarn with stdin redirected. Whenever I run this from msysgit/Git for Windows, it fails reading from stdin.

Example: echo 'h1{some:thing;}' | yarn run autoprefixer-cli

(npx works)

If the current behavior is a bug, please provide the steps to reproduce.

$ ./repro.sh
yarn run v1.3.2
$ D:\Users\agross\Downloads\yarn-run-windows\node_modules\.bin\autoprefixer-cli
events.js:183
      throw er; // Unhandled 'error' event
      ^

Error: read EBADF
    at _errnoException (util.js:1022:11)
    at Pipe.onread (net.js:615:25)
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

What is the expected behavior?
Same as on e.g. macOS:

$ ./repro.sh
yarn run v1.3.2
$ /Users/agross/Downloads/yarn-run-windows/node_modules/.bin/autoprefixer-cli
h1{some:thing;}
✨  Done in 0.80s.

Please mention your node.js, yarn and operating system version.

node 8.9.4
yarn 1.3.2
Windows 10 x64

[agross]

I see the same behavior on node 9.4.0.