Tapping the versions cask prevents upgrading virtualbox

I don’t understand what is going on

$ brew cask upgrade virtualbox
==> Upgrading 1 outdated package:
virtualbox 6.1.6,137129 -> 6.1.10,138449
==> Upgrading virtualbox
==> Purging files for version 6.1.10,138449 of Cask virtualbox
Error: Cask virtualbox-beta exists in multiple taps:
  homebrew/cask-versions/virtualbox-beta
  caskroom/versions/virtualbox-beta
$ brew cask remove homebrew/cask-versions/virtualbox-beta
Error: Cask 'virtualbox-beta' is not installed.
$ brew cask remove caskroom/versions/virtualbox-beta
Error: Cask 'virtualbox-beta' is not installed.

What is the problem? I’m really not trying to do anything with virtualbox-beta.

$ brew cask install virtualbox
Error: Cask virtualbox-beta exists in multiple taps:
  homebrew/cask-versions/virtualbox-beta
  caskroom/versions/virtualbox-beta

I can’t install it anymore either. Is there a way to specify that the package I really want to interact with is “virtualbox”? Is there a way to specify “virtualbox” exactly without specifying anything about “virtualbox-beta”? Maybe some regex or something?

What does brew tap say?

It used to say
caskroom/versions
homebrew/cask
homebrew/cask-versions
homebrew/core

I got rid of the first one and I guess stuff is working now. Maybe I tapped it by accident? Why was brew trying to mess with virtualbox-beta anyway?

If you try and install something brew will load all definitions to see what you mean and throw errors if it fails to load them. The fact that virtualbox-beta was throwing an error was purely coincedental.