vagrant 2.2.6 box update error

gistfile1.txt

~/vagrant/osx/mojave Ollie$ vagrant box update
==> default: Checking for updates to 'yzgyyang/macOS-10.14'
    default: Latest installed version: 10.14.4
    default: Version constraints: 
    default: Provider: virtualbox
==> default: Updating 'yzgyyang/macOS-10.14' with provider 'virtualbox' from version
==> default: '10.14.4' to '10.14.6'...
==> default: Loading metadata for box 'https://vagrantcloud.com/yzgyyang/macOS-10.14?access_token=Hzu3YEDmgr2iPg.atlasv1.7DmsT8aUQYlScVlInTgDVZ7n7tTn4zyiC7zKpOscIdG1zmfSdIgYVSZ7L2tgIivry8Y'
==> default: Adding box 'yzgyyang/macOS-10.14' (v10.14.6) for provider: virtualbox
    default: Downloading: https://vagrantcloud.com/yzgyyang/boxes/macOS-10.14/versions/10.14.6/providers/virtualbox.box
==> default: Box download is resuming from prior download progress
    default: Download redirected to host: vagrantcloud-files-production.s3.amazonaws.com
    default: Calculating and comparing box checksum...
/opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/lib/vagrant/util/file_checksum.rb:65:in `load_digest': uninitialized constant FileChecksum::Errors (NameError)
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/lib/vagrant/util/file_checksum.rb:30:in `initialize'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/lib/vagrant/action/builtin/box_add.rb:533:in `new'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/lib/vagrant/action/builtin/box_add.rb:533:in `validate_checksum'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/lib/vagrant/action/builtin/box_add.rb:352:in `box_add'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/lib/vagrant/action/builtin/box_add.rb:283:in `add_from_metadata'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/lib/vagrant/action/builtin/box_add.rb:118:in `call'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/lib/vagrant/action/warden.rb:50:in `call'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/lib/vagrant/action/builtin/before_trigger.rb:23:in `call'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/lib/vagrant/action/warden.rb:50:in `call'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/lib/vagrant/action/builder.rb:116:in `call'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/lib/vagrant/action/runner.rb:102:in `block in run'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/lib/vagrant/util/busy.rb:19:in `busy'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/lib/vagrant/action/runner.rb:102:in `run'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/plugins/commands/box/command/update.rb:161:in `box_update'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/plugins/commands/box/command/update.rb:133:in `block in update_vms'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/plugins/commands/box/command/update.rb:120:in `each'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/plugins/commands/box/command/update.rb:120:in `update_vms'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/plugins/commands/box/command/update.rb:49:in `execute'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/plugins/commands/box/command/root.rb:66:in `execute'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/lib/vagrant/cli.rb:66:in `execute'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/lib/vagrant/environment.rb:290:in `cli'
	from /opt/vagrant/embedded/gems/2.2.6/gems/vagrant-2.2.6/bin/vagrant:182:in `<main>'