Android Client ignoring https in url, only hitting port 80

Android client app version 2.15.0 (Build 6000512)
This is not happening with everyone, only one or two people.

No matter how the URL is entered for the server, it is ignoring the https:// and trying to connect to port 80. Even when specifying the port with :443, it is still only trying port 80.
The app has been reinstalled. The data and cache wiped. The phone rebooted. Nothing has helped.
Connecting via the chrome browser on the phone works correctly, so there isn’t any network redirect in the way. It is only the app itself that is doing this.

Notice the “failed to connect” line specifying port 80, despite the url being https://

That is weird! Maybe ask in the mobile developers channel? Mattermost

If this was a computer, I’d fire up Wireshark or tcpdump and watch what was happening. And if it was happening in a browser, the Jabascript console would probably help. But on a mobile app…