bug: pnpm install doesn't settle

[paradoxloop]

Provide environment information

System:
    OS: macOS 15.2
    CPU: (8) arm64 Apple M2
    Memory: 99.22 MB / 16.00 GB
    Shell: 5.9 - /bin/zsh
Binaries:
    Node: 22.12.0 - /usr/local/bin/node
    npm: 10.9.0 - /usr/local/bin/npm
    pnpm: 9.15.3 - /opt/homebrew/bin/pnpm
    bun: 1.1.42 - ~/.bun/bin/bun

Describe the bug

Running pnpm install repeatedly results in pnpm reporting the adding or removing packages every time even though no changes to dependencies have been made.

I have never seen this behaviour before in a pnpm project. This might be expected behaviour however it feels like a bug?

Link to reproduction

[this repository]

To reproduce

Following install instructions in this repository:

1. npx create-turbo@latest -e https://github.com/t3-oss/create-t3-turbo
2. choose pnpm
3. cd into created folder
4. run pnpm install (even though pnpm install was run during setup)

Scope: all 14 workspace projects
Lockfile is up to date, resolution step is skipped
Packages: +21 -122

5. run pnpm install again

Scope: all 14 workspace projects
Lockfile is up to date, resolution step is skipped
Packages: -122

How ever many times you run pnpm install you get minus or plus some number of packages.

Additionally:
Running pnpm dedupe gets +19 packages
Then running pnpm install again gets you +15 -122 packages

Additional information

No response