failed install on windows 10

[denisfitz57]

after rebar3 repl
I get (after DEBUG set to 1):
.
.
.
a bunch of seeming successful stuff
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.
.

===> Running provider: lock
===> sh(cmd /q /c git -C "c:/Users/denis/Documents/undertone/_build/default/lib/rational" --work-tree="c:/Users/denis/Documents/undertone/_build/default/lib/rational" rev-parse --verify HEAD)
failed with return code 128 and the following output:
fatal: Invalid path '/c/Users/denis/Documents/undertone/_build/default/lib/rational/c:': No such file or directory

===> Locking of git dependency failed in c:/Users/denis/Documents/undertone/_build/default/lib/rational

[oubiwann]

Oof. No clue. Let's keep this open and maybe do some asking/poking around ...