Partner can unlock iPad with Touch ID after iPadOS update

• Remove the fingerprint and set it up again. If there is a problem with the fingerprint sensor, you will find that setup fails.
• Are you sure that a Passcode is not being entered?
• Is iPad Unlock is turned on in Touch ID Settings with a Passcode enabled?
• I have seen no reports of the update bypassing Touch ID, and if that was the case, these Support Pages would be filled with that issue.
• The odds of another person being able to open your iPad with their fingerprint is 1 in 50,000. It is not impossible, only improbable.

About Touch ID advanced security technology - Apple Support

• If you are not able to resolve the problem, then schedule an appointment with Apple for a diagnostics.

Genius Bar Reservation and Apple Support Options - Apple

Delete all your fingerprints and then enter only yours. Make sure you get good contact.

Use Touch ID on iPhone and iPad - Apple Support

If Touch ID isn't working on your iPhone or iPad - Apple Support