Cisco Umbrella supports SCIM-based provisioning of users and groups from Okta.
If the Umbrella SCIM server is unreachable from Okta at any point in time, then any user/group provisioning requests from Okta to Umbrella will fail till the time the Umbrella SCIM server is reachable. Okta does not retry any failed requests after the SCIM server becomes reachable again. So Umbrella will not be aware of any changes to users, groups or group memberships during this period.
These provisioning failures will however be captured on the Okta dashboard. On the Okta dashboard, you will be given the option to manually select specific events or all events to retry the push. On pushing these events, these changes will reflect on the Umbrella dashboard within a short period of time.