brew: brew cleanup: Error: Directory not empty @ dir_s_rmdir - /usr/local/Cellar/unbound/1.13.1

brew config output

HOMEBREW_VERSION: 3.2.9-9-gc9f4d1d
ORIGIN: https://github.com/Homebrew/brew
HEAD: c9f4d1d90076c08f8c20dcc9772796e49321ab22
Last commit: 3 hours ago
Core tap ORIGIN: https://github.com/Homebrew/homebrew-core
Core tap HEAD: 748c5b2c3bbbfd30e991616ebf74d8ab8c20179e
Core tap last commit: 18 minutes ago
Core tap branch: master
HOMEBREW_PREFIX: /usr/local
HOMEBREW_CASK_OPTS: []
HOMEBREW_MAKE_JOBS: 8
Homebrew Ruby: 2.6.3 => /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/bin/ruby
CPU: octa-core 64-bit kabylake
Clang: 12.0.5 build 1205
Git: 2.30.1 => /Library/Developer/CommandLineTools/usr/bin/git
Curl: 7.64.1 => /usr/bin/curl
macOS: 11.5.1-x86_64
CLT: 12.5.1.0.1.1623191612
Xcode: 12.5.1

brew doctor output

Please note that these warnings are just used to help the Homebrew maintainers
with debugging if you file an issue. If everything you use Homebrew for is
working fine: please don't worry or file an issue; just ignore this. Thanks!

Warning: Some installed formulae are deprecated or disabled.
You should find replacements for the following formulae:
  lua@5.1

Warning: Putting non-prefixed coreutils in your path can cause GMP builds to fail.

Warning: You have unlinked kegs in your Cellar.
Leaving kegs unlinked can lead to build-trouble and cause formulae that depend on
those kegs to fail to run properly once built. Run `brew link` on these:
  hyperkit
  kubernetes-cli
  six

• I ran brew update and am still able to reproduce my issue.
• I have resolved all warnings from brew doctor and that did not fix my problem.

What were you trying to do (and why)?

Updating all brew packages to get regular and security updates.

What happened (include all command output)?

brew update && brew upgrade && brew upgrade --cask --greedy Already up-to-date. ==> Upgrading 10 outdated packages: terraform 1.0.4 -> 1.0.5 wget 1.21.1 -> 1.21.1_1 pandoc 2.14.1 -> 2.14.2 pylint 2.9.6 -> 2.10.2 azure-cli 2.27.1 -> 2.27.2 pango 1.48.8 -> 1.48.9 semgrep 0.61.0 -> 0.62.0 harfbuzz 2.8.2 -> 2.9.0 glib 2.68.3 -> 2.68.4 freetds 1.3 -> 1.3.1 ==> Upgrading freetds 1.3 -> 1.3.1

==> Downloading https://ghcr.io/v2/homebrew/core/freetds/manifests/1.3.1 ######################################################################## 100.0% ==> Downloading https://ghcr.io/v2/homebrew/core/freetds/blobs/sha256:7457bdc77b8ab81151549422e00dcac1fc6a4701527cc01cac4a4c6a4020481 ==> Downloading from https://pkg-containers.githubusercontent.com/ghcr1/blobs/sha256:7457bdc77b8ab81151549422e00dcac1fc6a4701527cc01c ######################################################################## 100.0% ==> Pouring freetds–1.3.1.big_sur.bottle.tar.gz 🍺 /usr/local/Cellar/freetds/1.3.1: 1,262 files, 13.8MB ==> brew cleanup has not been run in 30 days, running now… Removing: /usr/local/Cellar/freetds/1.3… (1,261 files, 13.8MB) Removing: /usr/local/Cellar/unbound/1.13.1… (52 files, 5.3MB) Error: Directory not empty @ dir_s_rmdir - /usr/local/Cellar/unbound/1.13.1

What did you expect to happen?

I expected the updates to complete.

Step-by-step reproduction instructions (by running brew commands)

`brew cleanup`
Warning: Skipping azure-cli: most recent version 2.27.2 not installed
Warning: Skipping glib: most recent version 2.68.4 not installed
Warning: Skipping harfbuzz: most recent version 2.9.0 not installed
Warning: Skipping pandoc: most recent version 2.14.2 not installed
Warning: Skipping pango: most recent version 1.48.9 not installed
Warning: Skipping pylint: most recent version 2.10.2 not installed
Warning: Skipping semgrep: most recent version 0.62.0 not installed
Warning: Skipping terraform: most recent version 1.0.5 not installed
Removing: /usr/local/Cellar/unbound/1.13.1... (52 files, 5.3MB)
Error: Directory not empty @ dir_s_rmdir - /usr/local/Cellar/unbound/1.13.1