In-repo addon writing public files on build causes endless build loop on serve

I'm having difficulty with my in-repo addon writing to appDir/public. What I'd like to do is write out a JSON file on each build to be included in the app /dist. The problem I'm running into is when running "ember serve", the file watcher detects the new file and rebuilds again, causing an endless loop.

I've tried writing the JSON file using preBuild() and postBuild() hooks, saving to /public, but after build, the watcher detects it and rebuild over and over, writing a new file again each time. I also tried using my-addon/public folder and writing to that, same thing.

The only thing that partially works is writing on init(), which is fine, except I don't see the changes using ember serve.

I did try using the treeForPublic() method, but did not get any further. I can write the file and use treeForPublic(). This only runs once though, on initial build. It partially solves my problem, because I get the files into app dist folder. But I don't think ember serve will re-run treeForPublic on subsequent file change in the app.

Is there a way to ignore specific files from file watch? Yet still allow files to include into the build? Maybe there's an exclude watch property in ember-cli-build?

Here's my treeForPublic() , but I'm guessing my problems aren't here:

treeForPublic: function() {
    const publicTree = this._super.treeForPublic.apply(this, arguments);
    const trees = [];
    if (publicTree) {
        trees.push(publicTree);
    }
    // this writes out the json
    this.saveSettingsFile(this.pubSettingsFile, this.settings);
    trees.push(new Funnel(this.addonPubDataPath, {
        include: [this.pubSettingsFileName],
        destDir: '/data'
    }));

    return mergeTrees(trees);
},