@The Big Favorite Hi Deanna, and welcome to the community.  Looking at the source on that page, it looks like you have two different Klaviyo accounts associated with your Shopify account. 

If you look at “View Source” on that page, and do a search for klaviyo.js?company_id= I found two different Klaviyo Site IDs.  This can cause a “race condition” where sometimes one Klaviyo account is loaded (that has the Signup Form) or the other account is loaded (that doesn’t have a Signup Form). 

See here:

You should only ever have one Klaviyo Account per Shopify Instance.

This sometimes happens when you have a developer account and a different account for production, or sometimes when you’re in the Shopify Klaviyo App when someone accidentally registers a new Klaviyo Account instead of Logging into an existing account.

You can see which one is the correct Klaviyo Account by going to your Account → Settings → API Keys and see what your Public API Key is.  

If you have access to the other (rogue) account, simply remove the integration from Shopify.  If you don’t have access (or don’t know who on your team have access) or if that doesn’t work, you may have to contact Klaviyo Support to see if they can help you troubleshoot and see if they can disable that other account.  

Hope this helps and let us know if you were able to resolve the issue!