Hi clif.mcgilvray,
Please make sure you have enabled the setting: Settings > Advanced > Instant camera
Then, please try quickly pressing the volume button twice when the screen is turned off and locked.
If the problem still appears, please tell me your lock type, and show me a short video of the problem.
To share videos, please upload it to ASUS WebStorage (https://www.asuswebstorage.com/navigate/) and share the link with us.
Thank you 🙂