OTK 4.4 on APIGW 10.0 is used, which was upgraded from APIGW 9.4 environment.
It was found that OAuth Manager behavior changed for the custom field when registering a new client. If you list the new client key, JASON value is already populated in the client_key_custom now.
However, updating the client_key_custom value of such a parameter as Scope, UI inconsistency is observed. Even if you update the Scope value in the Edit Client Key page, the Custom Field (client_key_custom) does not reflect the update, i.e, the old Scope value is still retained.
This is also observed in OTK 4.6.
Broadcom is aware of this UI inconsistency issue and will update this document when a solution becomes available.
These fields are not for OTK internal use. Such inconsistency should not have any bad impact when you leave them as they are. It depends on your requirement to use these fields.