Hi Peter- looks like Bryan from our support team replied offline to you so posting here in case others have a similar question:

Hello Pete,

As far as we're aware, there aren't any issues associated with China with QR code. It looks like you're going through an MFA enrollment using Okta verify which requires the QR code scan. A few things to check are:

• are there any restrictions for users in China in your setup for MFA enrollment?
• Is the behavior consistent with both Android and iOS specific to any versions? 

You can also configure an account manually by doing the following:

• On their mobile device, end users start the Okta Verify app, then tap Add Account on iOS, or + on Android.
• From the barcode page, they tap No barcode?.
• In the Okta Account field, end users enter their Okta username (for example, ted@mycompany.com).
• From their computer, end users click the Can’t scan the QR code link to obtain the secret key which they enter in the Secret Key field on their mobile device. End users tap Save.
• The pass code generator screen appears and generates the codes end users use when they are prompted for extra verification.
• End users have 30 seconds to enter the pass code before it generates a new one.

Please reference the following article for more details: https://help.okta.com/en/prod/Content/Topics/Mobile/Okta_Verify_Using.htm

If you need further assistance, feel free to create a case with us and we'll investigate further.