Unexpected warning while building transforming image-set urls with less

[GarreltMock]

Describe the bug

We use less as css preprocessor. There we have a setup with mixins filling image-sets.
After this commit:d59efd8 we get vite:resolve warnings.

VITE_ASSET__BgDL8UKD referenced in VITE_ASSET__BgDL8UKD didn't resolve at build time, it will remain unchanged to be resolved at runtime

The build css file looks correct to me though.

The less code looks like this:

.image-from-set(@prop; @path-1x) {
    @{prop}: image-set(@path-1x 1x);
}

.test {
    .image-from-set(background-image, url("./img.png"));
}

The warning is only shown on images that can not be inlined.

Reproduction

https://github.com/GarreltMock/vite-bug-repro

Steps to reproduce

npm install then npm run build

System Info

System:
    OS: macOS 15.2
    CPU: (10) arm64 Apple M1 Max
    Memory: 1.55 GB / 64.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.6.0 - ~/.nvm/versions/node/v22.6.0/bin/node
    Yarn: 1.22.22 - /opt/homebrew/bin/yarn
    npm: 10.8.3 - ~/.nvm/versions/node/v22.6.0/bin/npm
    pnpm: 9.10.0 - ~/.nvm/versions/node/v22.6.0/bin/pnpm
    bun: 1.0.11 - ~/.bun/bin/bun
  Browsers:
    Chrome: 132.0.6834.111
    Safari: 18.2
  npmPackages:
    vite: ^6.0.5 => 6.0.11

Used Package Manager

npm

Logs

transforming (1) src/main.js
VITE_ASSET__BgDL8UKD referenced in VITE_ASSET__BgDL8UKD didn't resolve at build time, it will remain unchanged to be resolved at runtime
✓ 4 modules transformed.
dist/index.html 0.45 kB │ gzip: 0.29 kB
dist/assets/img-CVimqOIp.png 157.17 kB
dist/assets/index-CzC1NDFV.css 0.12 kB │ gzip: 0.09 kB
dist/assets/index-Dq8oS-Aj.js 0.83 kB │ gzip: 0.46 kB
✓ built in 97ms

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• The provided reproduction is a minimal reproducible example of the bug.