npmInstall ignores npm workspaces in up-to-date detection

We have a monorepo with multiple workspaces. The workspaces also reflect the gradle (sub)project structure.
Our project structure looks like this:

build.gradle
package.json
package-lock.json
node_modules/
scripts/
\_ build.gradle
|_ package.json

The root package.json defined scripts/ as a workspace:

  "workspaces": [
    "scripts"
  ]

We apply the gradle-node-plugin in the scripts/build.gradle like this:

node {
    nodeProjectDir = rootProject.projectDir
}

task compile(type: NpmTask) {
    dependsOn = [tasks.npmInstall]
    workingDir = rootProject.projectDir
    args = [
        "run",
        "build",
    ]
}

The problem is that npmInstall only registers changes to the root package.json etc., but not to scripts/package.json etc.
So if I change a dependency in scripts/package.json, npmInstall might not run.
It would be nice if the npmInstall task could check for changes in package.json etc. in all workspaces defined in the root package.json as well.
Currently, we need this workaround:

npmInstall {
    outputs.upToDateWhen {false}
}

I don't think the problem is related to our unusual project structure, but likely affects every situation where NPM workspaces are involved - NpmInstallTask just doesn't seem to consider changes to workspace files / npm files outside of nodeProjectDir at all.

Start with src/main/kotlin/com/github/gradle/node/npm/task/NpmInstallTask.kt and inspect how npmInstall declares inputs for up-to-date detection. Compare those inputs with the root package.json workspace entries and the workspace package files described in the issue. Done means changes in workspace package.json or related npm files cause npmInstall to run, with coverage in the relevant existing task tests.