iPad Pro charging to 100% even though I have 80% limit set

Your iPad can be expected to occasionally charge to 100% even when choosing to limit charging to 80%. This strategy is deliberate, being necessary to calibrate charging and maintain battery health.

That said, if your iPad is unexpectedly always charging to 100%, 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

A settings reset is relatively benign - and shouldn't affect any data stored on your device. It is, however, strongly recommended that you ensure that you always have a backup of your locally stored data.

By contrast to a reset of your iPad setting, a factory restore will completely reset and erase all locally stored data from your iPad. However, you can restore your data from your iCloud or iTunes backup.

You're very welcome. I'm delighted to learn that the problem has been successfully resolved.