CA Service Desk Manager 17.x / iOS devices 11.x
This behavior was identified as a defect.
It happens only for mobile devices running iOS release 11.
It works fine for Android devices.
Engineering made the code changes and fixed it as part of mobile app build 3.1.13.
If using mobile app release previous to this point release (ex. 3.1.12), you should update the application or deleting the app and installing it again from Apple Store by searching for "CA Service Management".