Subversion migration error

I am trying to migrate from a subversion repo on to a git one, and I'm having difficulties.

I am using the Mac command line client version 1.7.5.4, and issuing this command:

/usr/local/git/bin/git svn clone https://[server]/svn -A svn.authorsfile --stdlayout --no-metadata

It downloads happily for 11611 out of ~27000 revisions, then dies with:

Found possible branch point: https://[server]/svn/trunk => https://[server]/svn/branches/interface-controller-redesign, 11611
Use of uninitialized value $u in substitution (s///) at /usr/local/git/libexec/git-core/git-svn line 1738.
Use of uninitialized value $u in concatenation (.) or string at /usr/local/git/libexec/git-core/git-svn line 1738.
refs/remotes/trunk: 'https://[server]/svn' not found in ''

It seems that I have a branching not covered in the --stdlayout that I wasn't aware of, but it would be nice to have a more graceful failure.