I'm not sure about the details of the phone you are using, but maybe your update introduced a new browser or browser version, we would need more details. I don't really think the android release should impact on how the browser handles opened pages, HTML5-wise, but the browser may be sending an user-agent not known by ExtJS Modern 6.2.1 and it is assuming you're in a non-android version.
Do you know what exact browser (name and version) your phone has?
Maybe if you can provide the user-agent it passes to browsers we could try to reproduce this specific suspicion at our side. You can get the user-agent your phone is sending to websites by several ways, maybe the simplest would be visiting a website that tells you that, like https://www.whoishostingthis.com/tools/user-agent/
After we check this we can further check more details. Did you test your phone on our examples explorer? If so, providing a page URL and what exactly happens (or doesn't) while trying to access with your phone would help us reproducing the issue.