This is an update regarding removal of a feature from CRM integration. Recently we identified that the option 'Fetch Accounts Fields' in the Instant sync was not working as expected so we're forced to remove it for any new syncs. However the same will work for all periodic syncs. Our team is working on a fix and the same will be available again once it has been sorted out.
Anyone who used this option in the instant sync beware that the accounts field data will not be fetched in the sync. But the contacts fields will be synced properly to campaigns.