Cannot reset password: incorrect "Don't know your passcode?" message

My wife does not remember her Apple ID password. She can use her iPhone fine and knows her correct passcode, which has been working for years.

When she tries to download an app from the App Store, she's prompted for her password and starts to go through the Forgot Password flow. She enters her Apply ID, and then gets brought to a screen to Enter Passcode. She enters the correct Passcode, and gets taken to a screen that says "Don't Know Your Passcode? Since you could not complete the previous step, you will have to wait to reset your password. The waiting period may be several days. We know this delay is inconvenient, but we use this time to ensure your account and data remain safe. Apple Support cannot reduce your wait time."

We've gone through the Reset Password flow on the Apple Support app on my iPhone (for a different Apple ID) and come to the same screen. She's nervous about continuing because she's afraid she'll get locked out of her phone.

Why is this "Don't Know Your Passcode?" message appearing when she does know her Passcode?