my example can get the feature on the current layer, and can tell whether it is the pop-up layer
constructor () {
state.map.on ('click', this.clickSouth);
}

clickSouth = (evt) = > {

    let coordinate = evt.coordinate;
    /*  */
    this.clickSouth = coordinate;
    /*  */
    let pixel = this.mapObj.map.getEventPixel(evt.originalEvent);
    let feature = this.mapObj.map.forEachFeatureAtPixel(pixel, function (feature, layer) {
        if (layer === this.mapObj.portLayer) {
        ......
        }  

}

Click (feature,layer,element,popLayer) {

    $("-sharppopup-content").html(feature.G.disInfo);
    popLayer.setPosition(this.clickSouth);
    $("-sharppopup").removeClass('popup_');
}