keybase decrypt -i flag appears to not work on Windows

PS > cat in.txt
Minimal reproduction

PS > keybase encrypt -i in.txt tekacs > out.txt

PS > keybase decrypt -i out.txt
- ERROR unknown stream format

PS > cat out.txt | keybase decrypt
Message authored by tekacs
Minimal reproduction

PS > cat out.txt
BEGIN KEYBASE SALTPACK ENCRYPTED MESSAGE. kiPgBwdlv6bV9N8 dSkCbjKrku6J44l ZW6CQ2AEutaJdpU T1bYDgRYHzVjdEL k6X5ikqpxLLGKU7 qFbK0UiwIQbAfMA Kvqx9y1aeyLV5EJ 2I5mRrsnb5xtlab T5mDiV47x8RiA2n s4HqNNzYRk3abyq htYP5L
1JXx3LVKG Xhzdzqz2m31QKan 7IEszVhUWhF4TyE zX5Z9TwA0aNo1PT moxHUT8VkiVMuc5 UffRWX31IrOlemv Vhg4zFhn6xjNUk0 VcP2v10nqW5vzN9 ZKMPiBdSn4FS4lA YudBRYNFg0PPI3k WqTXrzJ0wFeHqoI jYvmhuaheNxevPQ ey7FuOq2NzajVlf q0QZdn
YrZesKCxS JBNys0UFTsNzdMR 9jgfJInH76BG6fX xUbqXiyzsyB01iy Q2T8CwVXLivs0R3 R5EGDeVU0N567aB jWe9FFWHUUTRQ8x 5ugjFPmCRMIwQ6U SSh2P6XcVhYLNbA Xpo9ykBKEkEoHjU vhyQmT2qOTLuz5D rcYkCcV2RDCFv4P eMDwIHKFYEYoFNP bL7Ta1
KiLsEuQ0c Eb3oInNnnMoQmVS 9dw6X2PYxflIzk5 JAK3qIUiAbE6szr PehKx5OmNWpVWGP 5l3kntAN5bu0hQv jSJE6GKAVW6PFtw qUAYYyQnvCGTOcE Ruz2hrgvw2Byttj slVIcJHbbwB6fkV V8jyQ6hqQ3CHgl2 GIh24aFClzylFyA Y0c7LFhuYwtkkU2 PmjtHs
xFAvXBaDc A1MuKVvSUS0K7CD KBimSQdQVUKu8Bw BKGtUVPAIBCZ4c1 WlF6cdp19E75g3h j9miO23r7Utvs07 xRiDMyx3iMM4vXT JadvQyNSknNvSDp 7nTRGAVreEFA8Yl qtu5RubgIGciDMa SLOME3JFxsJgGLA ujU2QQmarSiD492 lAK8bUOijcMUtnE aLF9Fm
NJy4TQl5j 2urs8Sm5XYb1eFQ 8etN9nhgLah2Hpn fNVI8TRFF1LWAD5 U9r7o7wIW72OmbK kVvLweDGEIcFjHm VGff9hL9G95FFeu 4I1xNcm4. END KEYBASE SALTPACK ENCRYPTED MESSAGE.

This is on Windows PowerShell (hence cat). Unless I'm fundamentally misunderstanding something, the -i flag to keybase decrypt appears to be broken (note the unknown stream format error).

The exact same sequence of steps (above), works correctly on a Linux machine, with keybase decrypt -i file and cat file | keybase decrypt giving the same result.

Windows version: keybase version 1.0.17-20160908172133+f09996a
Linux version: keybase version 1.0.17-20160926184414+70d1a33

The [stream matching code][matching-code] hasn't been updated since Mar 30 and seems correct, so I assume this is something to do with reading, if anything?

Reproduce the listed keybase encrypt/decrypt commands in Windows PowerShell and on Linux, comparing file input with piped input. Start by inspecting the stream matching code and the input-handling path; done means keybase decrypt -i file produces the same result as piping that file to keybase decrypt on Windows.