Wrong output when using master~3 as ref for git gem

[segiddins]

Note master~@ is missing the 3

Fetching https://github.com/bbatsov/rubocop.git
Fetching gem metadata from https://rubygems.org/..............
Fetching version metadata from https://rubygems.org/.
Resolving dependencies...
Using rake 12.0.0
Using parallel 1.11.1
Using ast 2.3.0
Using powerpack 0.1.1
Using ruby-progressbar 1.8.1
Using unicode-display_width 1.2.1
Using bundler 1.15.0.pre.2
Using rainbow 2.2.2
Using parser 2.4.0.0
Using rubocop 0.48.1 from https://github.com/bbatsov/rubocop.git (at master~@9d428ed)
Bundle complete! 1 Gemfile dependency, 10 gems now installed.
Use `bundle info [gemname]` to see where a bundled gem is installed.

Environment

Bundler   1.15.0.pre.2
Rubygems  2.6.11
Ruby      2.4.1p111 (2017-03-22 revision 58053) [x86_64-darwin16]
GEM_HOME  /Users/segiddins/.gem/ruby/2.4.1
GEM_PATH  /Users/segiddins/.gem/ruby/2.4.1:/Users/segiddins/.rubies/2.4.1/lib/ruby/gems/2.4.0
Git       2.11.0
Platform  x86_64-darwin-16

Bundler settings

gem.test
  Set for the current user (/Users/segiddins/.bundle/config): "rspec"
gem.mit
  Set for the current user (/Users/segiddins/.bundle/config): "true"
gem.coc
  Set for the current user (/Users/segiddins/.bundle/config): "true"
plugins
  Set for the current user (/Users/segiddins/.bundle/config): "true"
allow_offline_install
  Set for the current user (/Users/segiddins/.bundle/config): "true"

Gemfile

Gemfile

gem "rubocop", :git => "https://github.com/bbatsov/rubocop.git", ref: "master~3"

Gemfile.lock

GIT
  remote: https://github.com/bbatsov/rubocop.git
  revision: 9d428edb838ed67eee11fc56fd8feeea0b7f0b11
  ref: master~3
  specs:
    rubocop (0.48.1)
      parallel (~> 1.10)
      parser (>= 2.3.3.1, < 3.0)
      powerpack (~> 0.1)
      rainbow (>= 1.99.1, < 3.0)
      ruby-progressbar (~> 1.7)
      unicode-display_width (~> 1.0, >= 1.0.1)

GEM
  remote: https://rubygems.org/
  specs:
    ast (2.3.0)
    parallel (1.11.1)
    parser (2.4.0.0)
      ast (~> 2.2)
    powerpack (0.1.1)
    rainbow (2.2.2)
      rake
    rake (12.0.0)
    ruby-progressbar (1.8.1)
    unicode-display_width (1.2.1)

PLATFORMS
  ruby

DEPENDENCIES
  rubocop!

BUNDLED WITH
   1.15.0.pre.2