Well in my Samsung M30 i have "Camera" App and "Camera Test" App.
The behavior i am seeing when i am start camera app and turn on front camera then this camera test app become active and normal camera app doe not respond and gives message that 2 camera app can not run same time.
When i force stop camera test app then normal camera app runs fine.
This started after i have received the latest update 2-3 weeks back.
In order to examine the issues occurring in your device, kindly send us the error log files using Samsung member application by following below mentioned path-
Open Samsung member app>click on “+“icon>send feedback>Error reports>attach log file.
Note: For better assistance, please send device log files within 15 minutes of issue occurrence along with the exact issue details.
Team Samsung Members