iPad turns off
Why does my iPad turn itself on after I have plugged it in to charge and turned it off manually? Within seconds, it turns itself back on.
iPad mini 6, iPadOS 17
Your iPad will, by design, automatically boot to a running state when connected to its Power Adapter. While there is no technical benefit in doing so, you should be able to shut-down the iPad after the iPad starts to charge.
If the iPad continues to restart, this might suggest that your iPad or Power Adapter has a fault - or the Power Adapter is unsuitable/incompatible with your iPad.