Vagrant: La salida de progreso de descarga de rvm está dañada

Estoy trabajando en el aprovisionamiento a través del script de shell bash y un paso está provocando un comportamiento de salida extraño.

Específicamente el paso de instalación de RVM:

sudo -u vagrant -H sh -c "\curl -sSL https://get.rvm.io | bash -s stable --rails"

Esto genera la siguiente salida: inicialmente kosher, pero durante la fase que normalmente mostraría una barra de progreso, en cambio, cada carácter tiene su propia línea, como si las letras se transmitieran como acciones de impresión individuales.

==> default: Downloading https://github.com/wayneeseguin/rvm/archive/stable.tar.gz
==> default: Installing RVM to /home/vagrant/.rvm/
==> default:     Adding rvm PATH line to /home/vagrant/.profile /home/vagrant/.bashrc /home/vagrant/.zshrc.
==> default:     Adding rvm loading line to /home/vagrant/.bash_profile /home/vagrant/.zlogin.
==> default: Installation of RVM in /home/vagrant/.rvm/ is almost complete:
==> default:   * To start using RVM you need to run `source /home/vagrant/.rvm/scripts/rvm`
==> default:     in all your open shell windows, in rare cases you need to reopen all shell windows.
==> default: # Administrator,
==> default: #
==> default: #   Thank you for using RVM!
==> default: #   We sincerely hope that RVM helps to make your life easier and more enjoyable!!!
==> default: #
==> default: # ~Wayne, Michal & team.
==> default: In case of problems: http://rvm.io/help and https://twitter.com/rvm_io
==> default: rvm 1.25.27 (stable) by Wayne E. Seguin <[email protected]>, Michal Papis <[email protected]> [https://rvm.io/]
==> default: Searching for binary rubies, this might take some time.
==> default: No binary rubies available for: ubuntu/14.04/i386/ruby-2.1.2.
==> default: Continuing with compilation. Please read 'rvm help mount' to get more information on binary rubies.
==> default: Checking requirements for ubuntu.
==> default: Requirements installation successful.
==> default: Installing Ruby from source to: /home/vagrant/.rvm/rubies/ruby-2.1.2, this may take a while depending on your cpu(s)...
==> default: ruby-2.1.2 - #downloading ruby-2.1.2, this may take a while depending on your connection...
==> default:  
==> default:  
==> default: %
==> default:  
==> default: T
==> default: o
==> default: t
==> default: a
==> default: l
==> default:  
==> default:  
==> default:  
==> default:  
==> default: %
==> default:  
==> default: R
==> default: e
==> default: c
==> default: e
==> default: i
==> default: v
==> default: e
==> default: d % Xferd  Average Speed   Time    Time     Time  Current
==> default:                                  Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
==> default:  
==> default:  
==> default: 0
==> default:  
==> default:  
==> default:  
==> default:  
==> default:  
==> default: 0
==> default:  
==> default:    0     0    0     0      0      0 --:--:--  0:00:01 --:--:--     0
  0     0    0     0    0     0      0      0 --:--:--  0:00:02 --:--:--     0
  0     0    0     0    0     0      0      0 --:--:--  0:00:03 --:--:--     0
  0     0    0     0    0     0      0      0 --:--:--  0:00:04 --:--:--     0
==> default:  
==> default:  
==> default: 0
==> default:  
==> default:  
==> default:  
==> default:  
==> default:  
==> default: 0
==> default:  
==> default:  
==> default:  
==> default:  
==> default: 0
==> default:  
==> default:  
  0     0    0     0    0     0      0      0 --:--:--  0:00:05 --:--:--     0
==> default:  
==> default:  
==> default: 8
==> default:  
==> default: 1
==> default: 1
==> default: .
==> default: 4
==> default: M
==> default:  
==> default:  
==> default:  
==> default:  
==> default: 8
==> default:  
==> default:  
==> default: 9
==> default: 6
==> default: 1
==> default: k
==> default:  
==> default:  
==> default:  
==> default:  
==> default: 0
==> default:  
==> default:     0   146k      0  0:01:20  0:00:06  0:01:14  237k
==> default:  
==> default: 31 11.4M   31 3694k    0     0   488k      0  0:00:23  0:00:07  0:00:16  916k
==> default:  
==> default: 8
==> default: 3
==> default:  
==> default: 1
==> default: 1
==> default: .
==> default: 4
==> default: M
==> default:  
==> default:  
==> default:  
==> default: 8
==> default: 3
==> default:  
==> default: 9
==> default: 7
==> default: 6
==> default: 1
==> default: k
==> default:  
==> default:    0     0  1141k      0  0:00:10  0:00:08  0:00:02 2429k
==> default: 1
==> default: 0
==> default: 0
==> default:  
==> default: 1
==> default: 1
==> default: .
==> default: 4
==> default: M
==> default:   100 11.4M    0     0  1325k      0  0:00:08  0:00:08 --:--:-- 3558k
==> default: ruby-2.1.2 - #extracting ruby-2.1.2 to /home/vagrant/.rvm/src/ruby-2.1.2
==> default: ...
==> default: ruby-2.1.2 - #configuring

Esto parece posiblemente relacionado con https://github.com/mitchellh/vagrant/issues/471 , aunque ese problema se manifestó de manera diferente (duplicación de líneas en lugar de segmentación de caracteres).

Medio ambiente:
Vagabundo 1.6.2
Linux Mint 16 (Petra)