Yes this comes form klaviyo and you can stop this confirmation from klaviyo settings
may this help
https://community.klaviyo.com/sign-up-forms-38/how-to-delete-double-opt-in-confirmation-email-2618
Topic summary
A user wants to remove the double opt-in confirmation email that appears after customers subscribe via email on their Shopify store (whynotcity.com/lahyoo). The confirmation form is generated by Klaviyo.
Suggested Solution:
- Change the Klaviyo settings from double opt-in to single opt-in
- A community link was provided with instructions on disabling the double opt-in confirmation
Current Issue:
- The user attempted to switch to single opt-in in Klaviyo settings but encountered a restriction showing “only double” is available
- The issue remains unresolved, with the user seeking additional guidance on how to bypass this limitation