Hi @nambirajanks, welcome back to the community.

Looking at what you presented, there may be a few explanations:

• Are there any other ways Subscribers can enter your “�CT] canvas newsletter” List? You can quickly find out by going to the List, and clicking on the “List Growth” tab to see where else people may be entering your Lists.  
• Does your Ecommerce Platform Integration (e.g. Shopify) also add users to the List through optins?  Typical places might be on Checkout, or on Account Registration or Creation.  You can check if you have that List selected in the integration settings of your ecommerce platform in Klaviyo.  
• Do you have any third party tools like Surveys, Quizzes, Customer Service/CRM, or Popups that might be adding subscribers to the List?
• Have you recently uploaded or imported a CSV of email addresses into that List?

Try to trace a few of those scenarios as I  suspect there are others ways then the single Form that submits to the List.

Hope that helps!