Issue with PlayCanvas Button and HTML Input Focus on Smartphone Controls

I have set up PlayCanvas’ Button Element to focus on a HTML input when clicked. But on touch controls on a smartphone, while it does focus, the soft keyboard does not show up.

I have prepared a project that reproduces the problem at the following link.
https://playcanvas.com/project/1152000/

This might be an issue with Canvas, but do you have any solutions?