This has been a known issue in these communities for over a year, now.
This is both an iOS 12 and iPadOS 13 issues with a growing minority of iPad Pro models across all 3-4 model years.
Your iPad Pro may be one of the minority units affected.
Try the new hard reset procedure for the new 2018 iPad Pro models.
1. Press and release the volume UP button.
2. Then immediately press and release the volume DOWN button.
3. Then, press and hold the Power button at the top. You will see the Slide to Power off button, but keep on holding down the Power button until you see the Apple logo, then let it go.
Once you have performed all the steps, wait for a few seconds and your 2018 iPad Pro will boot up completely to the iPad Pro’s Lock screen.
Good Luck!