b0c5843 seems to have broken pacote on Windows. I'm not really sure how, or why, but you can see the failure here: https://ci.appveyor.com/project/zkat/pacote/build/1.0.876/job/462gfat2t5gpb0ry#L144, which has to do with pacote's onentry shenanigans.

I installed 4.4.1 and the problem went away, so I assume it's that specific commit causing it.