Hi there, kindly let us know the following details:
1 . Name of the device
2 . Request you to provide us with your device's latest firmware version. You can follow the below instructions to do the same: Settings -- About -- Software Information
3 . Let us know during what usage the ghost touch occurs.
4. Can you share a video probably from a different phone, if the device is unusable.
5. Have you tried factory reset after new FOTA? Its recommended to factory reset your phone after a new update.
You may follow the below steps also:
1. Clear system cache.
2. Try the same under safe mode:
Hold the power button for 5 seconds => When the screen flashes with option => Press & hold power option => You will get an option to restart in safe mode
3. If still you face the issue
factory reset your phone after taking a full backup :
https://www.asus.com/support/FAQ/1006346/