Error: Unexpected method 'appcast' called on Cask transmission-remote-gui.

[muttmutt]

Verification

• I understand that if I ignore these instructions, my issue may be closed without review.
• I have retried my command with --force.
• I ran brew update-reset && brew update and retried my command.
• I ran brew doctor, fixed as many issues as possible and retried my command.
• I have checked the instructions for reporting bugs.
• I made doubly sure this is not a checksum does not match / SHA256 mismatch error (do not open an issue before trying to open a PR to fix first).

Description of issue

Error: Unexpected method 'appcast' called on Cask transmission-remote-gui.

Command that failed

brew update

Output of command with --verbose --debug

brew update --verbose --debug is too long to paste here. I put it on pastebin.

https://pastebin.com/0T268mmf

Output of brew doctor and brew config

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 kegs have no formulae!
This means they were either deleted or installed manually.
You should find replacements for the following formulae:
  python-magic
  python-markupsafe

Warning: Some installed formulae are deprecated or disabled.
You should find replacements for the following formulae:
  lua@5.3
  openssl@1.1
  python-dateutil
  python-lxml
  simh
  youtube-dl

Warning: Unbrewed dylibs were found in /usr/local/lib.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae and may need to be deleted.

Unexpected dylibs:
  /usr/local/lib/libfuse.0.dylib
  /usr/local/lib/libfuse_ino64.dylib
  /usr/local/lib/libosxfuse.dylib
  /usr/local/lib/libosxfuse_i64.dylib

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:
  gcc
  numpy
  certifi
  gnupg

HOMEBREW_VERSION: 4.3.1
ORIGIN: https://github.com/Homebrew/brew
HEAD: e0bc557e7b991cb23583679e1cf1c8a92b793aeb
Last commit: 6 days ago
Core tap JSON: 26 May 00:11 UTC
Core cask tap JSON: 26 May 00:11 UTC
HOMEBREW_PREFIX: /usr/local
HOMEBREW_CASK_OPTS: []
HOMEBREW_DISPLAY: /private/tmp/com.apple.launchd.b88MOUyNys/org.xquartz:0
HOMEBREW_MAKE_JOBS: 12
Homebrew Ruby: 3.3.1 => /usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/3.3.1/bin/ruby
CPU: dodeca-core 64-bit kabylake
Clang: 15.0.0 build 1500
Git: 2.39.3 => /Library/Developer/CommandLineTools/usr/bin/git
Curl: 8.6.0 => /usr/bin/curl
macOS: 14.5-x86_64
CLT: 15.3.0.0.1.1708646388
Xcode: 15.4

Output of brew tap

cloudflare/cloudflare
coursier/formulas
eugmes/fntsample
gromgit/fuse
homebrew-ffmpeg/ffmpeg
homebrew/services
microsoft/mssql-release

[miccal]

See #173201 (comment).