Boots on power - iMac 27” 2019

My iMac 27” 2019 has started booting up when the power supply is switched on at the wall before I press power button on the iMac. I don’t know if this coincidence but I’ve just done an update to Monterey and it seems to have started at same time, could this be possibly why?

I’ve check energy saver setting and ‘start up automatically after power failure’ isn’t checked.

I’ve felt the power button and it doesn’t feel like it’s jammed in, it’s can still move and be pressed.

any other ideas folks???