Adding a new required field to an existing schema and client

I am trying to create add a new required field to an existing realm sync schema. Everything seems to work fine when adding the new field to the schema via the realm sync web portal. I can still add new items into the collection without modifying the client and new items have the field populated with the default value.

However, when attempting to add this new field to the client model it throws an error.
From reading the documentation this should be possible as it is an additive change.
Any idea why it would throw the following error? Or is there a different procedure for adding new required fields to existing schemas?

RealmSwift/SwiftUI.swift:277: Fatal error: 'try!' expression unexpectedly raised an error: Error Domain=io.realm Code=10 "Migration is required due to the following errors:
- Property 'Tag.newlyAddedText' has been added." UserInfo={NSLocalizedDescription=Migration is required due to the following errors:
- Property 'Tag.newlyAddedText' has been added., Error Code=10}
2021-06-30 12:59:49.244071+0100 RealmSyncTest[12157:3982699] RealmSwift/SwiftUI.swift:277: Fatal error: 'try!' expression unexpectedly raised an error: Error Domain=io.realm Code=10 "Migration is required due to the following errors:
- Property 'Tag.newlyAddedText' has been added." UserInfo={NSLocalizedDescription=Migration is required due to the following errors:
- Property 'Tag.newlyAddedText' has been added., Error Code=10}

Note, this app uses synced realms only, no local realms.

Thanks