Catalina install bug: zsh ownership

I’ve searched but been unable to find any posts on this topic, so I thought I’d make sure this was a known issue.

Brand new laptop, arrived with the latest release, 10.15.4. Docker and VirtualBox were both installed prior to me attempting to install brew, and both took up residency under /usr/local.

These errors popped up at the end of the install:

Error: Failed to link all completions, docs and manpages:
  Permission denied @ rb_file_s_symlink - (../../../Homebrew/completions/zsh/_brew, /usr/local/share/zsh/site-functions/_brew)
Failed during: /usr/local/bin/brew update --force

Despite that, the installation reported as successful, which is probably something that should be rectified.
These were displayed whenever I attempted any brew operations:

Error: The following directories are not writable by your user:
/usr/local/share/zsh
/usr/local/share/zsh/site-functions

You should change the ownership of these directories to your user.
  sudo chown -R $(whoami) /usr/local/share/zsh /usr/local/share/zsh/site-functions

And make sure that your user has write permission.
  chmod u+w /usr/local/share/zsh /usr/local/share/zsh/site-functions

Fortunately, following those instructions seems to have corrected the problem.