In Talkdesk, there are options available that can change when you receive calls in the browser. If you head over to the upper right hand side of the Dashboard, you will see your current Agent or Admin initials, with a drop-down for 'Agent Profile'.
If you check inside the override settings, you will see a couple override options which can cause the issue described. Make sure the settings below reflect when you would like to receive calls in the browser or on your external number.