Unable to take screenshot on iPhone 16 running iOS 18

Hi

I have the Iphone 16promax, and am completely unable to screenhot on the device using the volume up and side key.

I have updated to latest software (io18), done a hard restart, the assistive touch is off, unable to screenshot from siri or using the back tap - and still no luck.

Confirmed the buttons work individually.

As unable to screen shot through other methods, it appears to be a software issue.

Anyone have any advice?

[Re-Titled by Moderator]