Thanks for the video. What type of pbx do you have? is it On premise, hosted, Startup?
Could you kindly install the Beta app and see if you can still experience the issue?
You'd have to join the BETA program to get this update. Just launch the Play Store, search for 3CX, and while in the Apps information page (where you see Uninstall & Open) scroll down to where it reads "Join the Beta" and press "Join".
It may take a few minutes but once complete you will see the Update button available for you to install the latest Beta app.
At any time, you may leave the Beta program by following the same steps to where the app information page reads 'You're a beta tester' and tap on 'Leave'