I selected the option to "update Shopify profiles with Klaviyo data." Why haven't all of my Klaviyo contacts synced over to Shopify?
For existing profiles in Klaviyo, we will start syncing those fields to Shopify the next time Shopify syncs any data about them to us. This is because, for existing profiles, we need their Shopify ID in order to update their information in Shopify. For profiles created in Klaviyo after the checkbox is checked, we will sync them to Shopify immediately.