Using either the 'Extended' or 'Directory Sync' Provisioning strategies from Okta Provisioning to O365 locks out manual edits to the O365 user profile. This creates a barrier to certain edge case attribute management strategies.
Question: Can we correct this by directly building a custom attribute in UD and mapping it to O365?
Answer: Yes. Custom attributes in Okta can be synced to O365 even when the AD schema has not been extended.
This applies to Okta customers provisioning to Office 365 with either the Extended or Directory Sync level of Okta Provisioning enabled. It does not apply to the use of ADSync or AADConnect. Also, it does not apply to Okta customers provisioning to Office 365 with the Basic level of Okta Provisioning enabled