lab mr checkout -t (sometimes?) incorrectly sets up remotes

[zaquestion]

$ git mr checkout 1 -t
Updating nick
From gitlab.corp.tune.com:zaq/mr_assigner
 * [new branch]      master     -> nick/master
new remote: nick
From gitlab.corp.tune.com:zaq/mr_assigner
 * [new ref]         refs/merge-requests/1/head -> nick/weighted
fatal: A branch named 'weighted' already exists.
2018/06/06 18:34:04 mrCheckout.go:83: exit status 128

$ git pull nick weighted
fatal: Couldn't find remote ref weighted
fatal: The remote end hung up unexpectedly

$ git remote -v
nick    git@gitlab.com:zaq/mr_assigner.git (fetch)
nick    git@gitlab.com:zaq/mr_assigner.git (push)
origin  git@gitlab.com:zaq/mr_assigner.git (fetch)
origin  git@gitlab.com:zaq/mr_assigner.git (push)

The command should also be able to rerun and add the remote without causing an error.