iPad auto restart issue when connected to power

This might suggest that your Power Adapter may have a fault. Try substituting for a different compatible USB Power Adapter (rated at least 12W - USB-C 20W recommended); if the problem is resolved, you have identified the source of the problem.

If the problem persists with a different Power Adapter, try a forced-restart of your iPad - as this will often clear an isolated software issue:

Force restart iPad (models with Face ID or with Touch ID in the top button)

If your iPad doesn’t have the Home button, do the following:

1. Press and quickly release the volume button nearest to the top button.
2. Press and quickly release the volume button farthest from the top button.
3. Press and hold the top button.
4. When the Apple logo appears, release the top button.

Force restart iPad (models with the Home button)

Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.

If the problem persists after performing the restart, it may be necessary to reset your iPad settings. While this reset will not cause any loss of data, as a precaution, it is always wise to ensure that you have a current iCloud or iTunes backup before performing the reset:

How to back up your iPhone, iPad, and iPod touch - Apple Support

When you are happy to proceed, you can perform the reset from iPad settings:

Settings > General > Transfer or Reset iPad > Reset > Reset All Settings

If the problem still doesn’t clear, the next step is to reset the iPad to factory settings:

Restore your iPhone, iPad, or iPod to factory settings - Apple Support

Otherwise, you would be best advised to seek assistance directly from Apple Support. You can contact the Support Team using the Support link at top-right or bottom-left of this page. Alternatively and perhaps easier, you can initiate and manage your support cases using the excellent Apple Support App. If not already installed on your iPad, the App can be downloaded from the App Store:

https://apps.apple.com/app/apple-support/id1130498044

You might also visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to test and assess your iPad and Power Adapter - and you can explore your available options:

Genius Bar Reservation and Apple Support Options - Apple

If the iPad has been fully shut-down, by design the iPad will automatically restart when connected to its Power Adapter or other source of external USB power.

You can, however, shut-down a running iPad while it continues to charge. The iPad will remain shut-down unless charging power is interrupted - at which time, when charging is restored, the iPad will again restart.

If your iPad cannot be shut-down during charging, this would indeed be abnormal behaviour.

I hope this clarification of expected behaviour is helpful in understanding precisely how your iPad should behave while charging.

I do believe this is normal. It's designed so that if it gets plugged in it will turn on so you can use it while it is charging. Mine does this same thing