The private mode is required to receive calls because of iOS architecture. A Bluetooth accessory should continuously be connected to a phone to display calls and notifications from a notification center. Sorry, Apple developed iOS in this manner, we can't overcome it.
If you would like to see calls on Glance clock you need to switch it to the "private" mode. In this mode, the clock will display information and notifications only from your account.
If you want to share your clock with someone else, you should not use the "private" mode, and all other integrations will work for both of you.
If you activated the "private" mode and want to disable it, please switch it off in the Glance App then go to your phone Settings > Bluetooth and find "Glance clock_xx" there. Please go back to the Glance app, the app should show you a window to enter the 6-digits code that will be displayed on the Glance clock face.
NOTE: You need to activate (switch off and back on) the private mode after updating Glance App.