Hi Kevin
Thank you for your asking. Kindly provide the information below so that we can better assist you.
1. Your current firmware version. Is it WW-16.0420.2006.30?
Settings>System>About Phone>Software information>Build Number
2. Please try to enter "Safe Mode". If the function works well in Safe Mode yet the issue remains out of Safe Mode, please check on any disturbance from the installed 3rd party apps.
# How to enter and exit "Safe Mode"
https://www.asus.com/support/FAQ/1005163/3. Please try "the Factory Reset"
Settings>System>Reset options>Erase all data(factory reset)
Please note that once the Factory Reset is completed, all data, apps, settings and personal information will be deleted.
If the issue still remains after the Factory Reset, kindly let me know.