oh dang--just googled the #git error I'm getting and there are only 2 hits, and one of those is in a language I don't understand.
@rpardee ooh, intrigue!
Also, https://xkcd.com/979/
Freaky. The error only occurs if my working directory is a specified UNC. If I map a drive to the very same place and make my current working directory that drive letter, then it works just fine.
Very non-intuitive. Seems like it's got to be a bug in git, tho probably so obscure nobody else is going to care.