Auto-updating on every command

[iandol]

Additional Info

• I am using Windows Subsystem for Linux

Output of brew config

HOMEBREW_VERSION: 4.3.0-93-ge0bc557
ORIGIN: https://github.com/Homebrew/brew
HEAD: e0bc557e7b991cb23583679e1cf1c8a92b793aeb
Last commit: 56 minutes ago
Core tap HEAD: 5bf936344094c47eb3627ed83988b9b33d07f34e
Core tap last commit: 17 minutes ago
Core tap JSON: 20 May 09:46 UTC
HOMEBREW_PREFIX: /home/linuxbrew/.linuxbrew
HOMEBREW_CASK_OPTS: []
HOMEBREW_DISPLAY: :1
HOMEBREW_EDITOR: nvim
HOMEBREW_MAKE_JOBS: 16
HOMEBREW_SORBET_RUNTIME: set
all_proxy: http://127.0.0.1:20171
ftp_proxy: http://127.0.0.1:20171
http_proxy: http://127.0.0.1:20171
https_proxy: http://127.0.0.1:20171
no_proxy: localhost, 127.0.0.1, ::1
Homebrew Ruby: 3.3.1 => /home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/vendor/portable-ruby/3.3.1/bin/ruby
CPU: 16-core 64-bit skylake
Clang: N/A
Git: 2.34.1 => /bin/git
Curl: 7.81.0 => /bin/curl
Kernel: Linux 6.5.0-35-generic x86_64 GNU/Linux
OS: Ubuntu 22.04.4 LTS (jammy)
Host glibc: 2.35
/usr/bin/gcc: 11.4.0
/usr/bin/ruby: N/A
glibc: N/A
gcc@11: N/A
gcc: 14.1.0
xorg: N/A

Output of brew doctor

Warning: Some installed kegs have no formulae!
This means they were either deleted or installed manually.
You should find replacements for the following formulae:
  font-fantasque-sans-mono
  font-alegreya-sans
  font-libertinus
  font-jetbrains-mono
  font-recursive-code
  font-alegreya
  font-cascadia-code
  font-fira-code
  font-symbols-only-nerd-font
  font-stix

Warning: Some installed formulae are deprecated or disabled.
You should find replacements for the following formulae:
  openssl@1.1

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/LabJackM.h
  /usr/local/include/chipmunk/chipmunk.h
  /usr/local/include/chipmunk/chipmunk_ffi.h
  /usr/local/include/chipmunk/chipmunk_private.h
  /usr/local/include/chipmunk/chipmunk_structs.h
  /usr/local/include/chipmunk/chipmunk_types.h
  /usr/local/include/chipmunk/chipmunk_unsafe.h
  /usr/local/include/chipmunk/cpArbiter.h
  /usr/local/include/chipmunk/cpBB.h
  /usr/local/include/chipmunk/cpBody.h
  /usr/local/include/chipmunk/cpConstraint.h
  /usr/local/include/chipmunk/cpDampedRotarySpring.h
  /usr/local/include/chipmunk/cpDampedSpring.h
  /usr/local/include/chipmunk/cpGearJoint.h
  /usr/local/include/chipmunk/cpGrooveJoint.h
  /usr/local/include/chipmunk/cpHastySpace.h
  /usr/local/include/chipmunk/cpMarch.h
  /usr/local/include/chipmunk/cpPinJoint.h
  /usr/local/include/chipmunk/cpPivotJoint.h
  /usr/local/include/chipmunk/cpPolyShape.h
  /usr/local/include/chipmunk/cpPolyline.h
  /usr/local/include/chipmunk/cpRatchetJoint.h
  /usr/local/include/chipmunk/cpRobust.h
  /usr/local/include/chipmunk/cpRotaryLimitJoint.h
  /usr/local/include/chipmunk/cpShape.h
  /usr/local/include/chipmunk/cpSimpleMotor.h
  /usr/local/include/chipmunk/cpSlideJoint.h
  /usr/local/include/chipmunk/cpSpace.h
  /usr/local/include/chipmunk/cpSpatialIndex.h
  /usr/local/include/chipmunk/cpTransform.h
  /usr/local/include/chipmunk/cpVect.h
  /usr/local/include/labjackusb.h

Warning: Unbrewed static libraries 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 static libraries:
  /usr/local/lib/libchipmunk.a

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:
  pkg-config

Description of issue

Recently I see "Auto-updating Homebrew" on every command on Ubuntu. I do not have HOMEBREW_AUTO_UPDATE_SECS set. I do not see this on my macOS systems...

▶︎ brew update
==> Updating Homebrew...
Already up-to-date.
                                                                                                                                   
▶︎ brew install font-inconsolata
==> Auto-updating Homebrew...
Adjust how often this is run with HOMEBREW_AUTO_UPDATE_SECS or disable with
HOMEBREW_NO_AUTO_UPDATE. Hide these hints with HOMEBREW_NO_ENV_HINTS (see `man brew`).

▶︎ brew install lua
==> Auto-updating Homebrew...
Adjust how often this is run with HOMEBREW_AUTO_UPDATE_SECS or disable with
HOMEBREW_NO_AUTO_UPDATE. Hide these hints with HOMEBREW_NO_ENV_HINTS (see `man brew`).

If I deliberately set HOMEBREW_AUTO_UPDATE_SECS I still see the same behaviour:

▶︎ set-env HOMEBREW_AUTO_UPDATE_SECS 3600
                                                                                                                                   
▶︎ brew update
==> Updating Homebrew...
Already up-to-date.
                                                                                                                                   
▶︎ brew install lua
==> Auto-updating Homebrew...
Warning: lua 5.4.6 is already installed and up-to-date.
To reinstall 5.4.6, run:
  brew reinstall lua

Any ideas?