What is the white dot under the telco name

Is this a bug or does the white dot mean something?

Last night a white dot appeared under the telco's name.

The dot wasn't tied to the background image, for it would appear in other apps when they were launched.

Unlike other posts where people reported a white dot on the display, this appears to be a software problem because it would disappear on the screen asking you to confirm if you wanted to turn off your phone.

Turning the phone off and on again made the white dot go away.