Instantiating template and setting it's parent (strange coords)

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1

I started making pool manager. so far so good. I instantiate 100 templates and put them into array
they have common parent (container)

Container has position 0,0,0 (in editor)
and all instantiated elements have position 0,0,0 (set in code)

Root where container is is also at 0,0,0

why then this code

console.log(instance.getPosition() + "|" + instance.getLocalPosition());

gives me:

[-1, -1, 0]|[0, 0, 0]
with -1,-1,0 being position for each of instantiated elements?

// initialize code called once per entity
PoolManager.prototype.initialize = function () {

    let app = this.app;
    let template = app.assets.get(this.assetId);

    for (let i = 0; i < this.itemCount; i++) {

        let instance = template.resource.instantiate();

        instance.setLocalPosition(new pc.Vec3(0, 0, 0));
        this.container.addChild(instance);

        pool.push(instance);

        console.log(instance.getPosition() + "|" + instance.getLocalPosition());

        instance.enabled = false;
    }

};