HOMEBREW_NO_INSTALL_FROM_API=1 causes a lockfile conflict with [email protected] dependency

[DrMechanica]

Output of brew config

HOMEBREW_VERSION: 4.4.20-126-ge1a7553
ORIGIN: https://github.com/Homebrew/brew
HEAD: e1a7553a56e02abeabd0ef461bcdc4ae383184d8
Last commit: 5 hours ago
Branch: master
Core tap HEAD: 50a7936ebbf549e6e548b373d59802a6b0295520
Core tap last commit: 4 hours ago
Core tap JSON: 09 Feb 04:42 UTC
Core cask tap HEAD: c77a74d9e70a3474b11a09f5cc10214c4d97a300
Core cask tap last commit: 45 minutes ago
Core cask tap JSON: 09 Feb 04:42 UTC
HOMEBREW_PREFIX: /usr/local
HOMEBREW_CASK_OPTS: []
HOMEBREW_EDITOR: vim
HOMEBREW_MAKE_JOBS: 8
HOMEBREW_SORBET_RUNTIME: set
Homebrew Ruby: 3.3.7 => /usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/3.3.7/bin/ruby
CPU: octa-core 64-bit sandybridge
Clang: 10.0.0 build 1000
Git: 2.17.2 => /Applications/Xcode.app/Contents/Developer/usr/bin/git
Curl: 7.54.0 => /usr/bin/curl
macOS: 10.13.6-x86_64
CLT: 10.1.0.0.1.1539992718
Xcode: 10.1

Output of brew doctor

Warnings about my outdated system, etc.

Description of issue

I'm in the process of installing the latest llvm, after installing llvm@12 and then patching the install as detailed here: https://github.com/orgs/Homebrew/discussions/4949#discussioncomment-7799075
The problem I'm running into is that when attempting brew install llvm --cc=llvam_clang with HOMEBREW_NO_INSTALL_FROM_API=1, the install always fails with this error:

Error: A `brew install llvm --cc=llvm_clang` process has already locked /usr/local/Cellar/[email protected].
Please wait for it to finish or terminate it to continue.

This doesn't happen when HOMEBREW_NO_INSTALL_FROM_API is unset, but of course the patch is not applied so the install fails.
I would love anyone's insight on why setting this environment variable causes [email protected] to seemingly attempt to be installed twice concurrently. [email protected] is already installed and up to date, by the way.

[DrMechanica]

Ok, I'm a dummy. I had edited my z3 formula to depend on a personal tap with a custom [email protected] (from when [email protected] had install issues), which created a conflict where llvm was using the homebrew/core python and z3 was using the custom tapped one. Silly, but maybe the resolution will help some other weary internet traveler who forgot they did something similar.