homebrew-cask: Alfred 2.4+ detected, but local preferences file not found

I’m having the same error as #7216 - see my comment there.

As requested, I’ve run the link command with the debug flag:

❯ brew cask alfred link --debug                            
==> Creating directories
==> Reading Alfred primary preferences
==> Executing: ["/usr/bin/defaults", "read", "com.runningwithcrayons.Alfred-Preferences", "version"]
==> Reading Alfred primary preferences
==> Executing: ["/usr/bin/defaults", "read", "com.runningwithcrayons.Alfred-Preferences", "syncfolder"]
==> 2014-12-12 14:02:17.573 defaults[38188:333772] 
==> The domain/default pair of (/Users/alex/Library/Preferences/com.runningwithcrayons.Alf
Error: Alfred 2.4+ detected, but local preferences file not found. Try running Alfred first.
/usr/local/Cellar/brew-cask/0.50.0/rubylib/cask/cli/alfred.rb:50:in `assert_installed'
/usr/local/Cellar/brew-cask/0.50.0/rubylib/cask/cli/alfred.rb:56:in `link'
/usr/local/Cellar/brew-cask/0.50.0/rubylib/cask/cli/alfred.rb:33:in `run'
/usr/local/Cellar/brew-cask/0.50.0/rubylib/cask/cli.rb:81:in `run_command'
/usr/local/Cellar/brew-cask/0.50.0/rubylib/cask/cli.rb:121:in `process'
/usr/local/bin/brew-cask.rb:42:in `<top (required)>'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
/usr/local/Library/brew.rb:59:in `require?'
/usr/local/Library/brew.rb:142:in `<main>'

Here are my alfred preferences - there seems to be no syncfolder?

~/Library/Preferences  
❯ defaults read com.runningwithcrayons.Alfred-Preferences
{
    NSNavLastRootDirectory = "~/Applications";
    NSNavPanelExpandedSizeForOpenMode = "{750, 480}";
    "NSToolbar Configuration com.apple.NSColorPanel" =     {
        "TB Is Shown" = 1;
    };
    "NSWindow Frame alfredpreferences" = "79 115 1100 662 0 0 1280 777 ";
    lastTab = appearance;
    lastTabBuild = 308;
    lastTabTS = "439999406.510222";
    version = "2.5.1";
}

Perhaps because I haven’t synced my Alfred: