Add interactivity to POIs from different tilesets - mapbox

Question

I'm working on Mapbox Studio Tutorial and practicing adding interactivity on POIs on map.
https://docs.mapbox.com/help/tutorials/add-points-pt-3/
map.on('click', (event) => {
// If the user clicked on one of your markers, get its information.
const features = map.queryRenderedFeatures(event.point, {
layers: ['layer1',"layer2","layer3"]
});
if (!features.length) {
return;
}
const feature = features[0];
/*
Create a popup, specify its options
and properties, and add it to the map.
*/
const popup = new mapboxgl.Popup({ offset: [0, -15] })
.setLngLat(feature.geometry.coordinates)
.setHTML(
`<h3>${feature.properties.title}</h3><p>${feature.properties.description}</p>`
)
.addTo(map);
});
The error I get is that the title of POIs from layer2 and layer3 is shown as "undefined" while layer1's title can be shown when clicking it on the map.
I think "undefined" comes because the title is not stored in the feature property but have no clear idea how to do that correctly.
I tried some codes I got from the internet such as below:
if (features.length > 0) {
// Loop feature and concatenate property as HTML strings
let propertiesHTML = '';
features.forEach(feature => {
Object.entries(feature.properties).forEach(([key, value]) => {
propertiesHTML += `<p><strong>${key}:</strong> ${value}</p>`;
});
});
// Create and add a popup
const popup = new mapboxgl.Popup({ offset: [0, -15] })
.setLngLat(features[0].geometry.coordinates)
.setHTML(propertiesHTML)
.addTo(map);
With code at least map is shown, but there is no interactive popup shown when I click it.