Analyzing Ad Clicks vs. Conversions in Welcome Emails

I added an ad offer to my welcome email— I’m seeing a lot of clicks and little conversions. It seems like the clicks are inflated for some reason and are not accurate. I’m tracking through Bitly as well. Is there something that causes this? Is it scanners that are pre clicking links for security measures since it’s the first email these individuals are getting from me? Anyone has experience with this?