Unexpected method 'appcast' called on Cask adoptopenjdk8

[greatdaveo]

Output of brew config

(base) greatdaveo@users-MacBook-Air ~ % brew config

HOMEBREW_VERSION: 4.5.8
ORIGIN: https://github.com/Homebrew/brew
HEAD: c19f08b3e8ea46ba94bd9315c46c0dda10ead31c
Last commit: 3 days ago
Branch: stable
Core tap JSON: 26 Jun 19:06 UTC
Core cask tap JSON: 26 Jun 19:06 UTC
HOMEBREW_PREFIX: /opt/homebrew
HOMEBREW_CASK_OPTS: []
HOMEBREW_MAKE_JOBS: 8
Homebrew Ruby: 3.4.4 => /opt/homebrew/Library/Homebrew/vendor/portable-ruby/3.4.4/bin/ruby
CPU: octa-core 64-bit arm_firestorm_icestorm
Clang: 17.0.0 build 1700
Git: 2.50.0 => /opt/homebrew/bin/git
Curl: 8.7.1 => /usr/bin/curl
macOS: 15.4.1-arm64
CLT: 16.3.0.0.1.1742442376
Xcode: 16.3
Rosetta 2: false
(base) greatdaveo@users-MacBook-Air ~ %

Output of brew doctor

Error: Unexpected method 'appcast' called on Cask adoptopenjdk8.
Follow the instructions here:
  https://github.com/Homebrew/homebrew-cask#reporting-bugs
Error: Unexpected method 'appcast' called on Cask adoptopenjdk8.
Follow the instructions here:
  https://github.com/Homebrew/homebrew-cask#reporting-bugs
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: A newer Command Line Tools release is available.
Update them from Software Update in System Settings.

If that doesn't show you any updates, run:
  sudo rm -rf /Library/Developer/CommandLineTools
  sudo xcode-select --install

Alternatively, manually download them from:
  https://developer.apple.com/download/all/.
You should download the Command Line Tools for Xcode 16.4.


This is a Tier 2 configuration:
  https://docs.brew.sh/Support-Tiers#tier-2
Do not report any issues to Homebrew/* repositories!
Read the above document instead before opening any issues or PRs.


Warning: Some installed formulae are deprecated or disabled.
You should find replacements for the following formulae:
  icu4c@75
  protobuf@21

Warning: You have the following deprecated, official taps tapped:
  Homebrew/homebrew-services
Untap them with `brew untap`.

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/libwkhtmltox.0.12.6.dylib

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

Unexpected header files:
  /usr/local/include/node/*
  /usr/local/include/wkhtmltox/*

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:
  python@3.12
  mysql

Warning: Your Xcode (16.3) is outdated.
Please update to Xcode 16.4 (or delete it).
Xcode can be updated from the App Store.


This is a Tier 2 configuration:
  https://docs.brew.sh/Support-Tiers#tier-2
Do not report any issues to Homebrew/* repositories!
Read the above document instead before opening any issues or PRs.

Description of issue

When I run brew install mariadb, Homebrew auto-updates, then downloads all dependencies, but fails on the existing Cask adoptopenjdk8 with:
Error: Unexpected method 'appcast' called on Cask adoptopenjdk8.

This happens even though I’m not actively installing or touching adoptopenjdk8. It appears to come from the auto-update of my Casks. I have already:

Updated all taps (brew update ran automatically)

Searched existing issues and PRs for “appcast” and “adoptopenjdk8”

Verified my brew config and brew doctor show no other problems

But the error persists and blocks installations of other formulae.

Relevant casks

adoptopenjdk8

[gromgit]

Searching for "unexpected method appcast called on cask" on your favourite search engine should've surfaced the cause and workaround quite readily. This is the top match on both Google and DuckDuckGo: Homebrew/homebrew-cask#173201 (comment)