Dynamic script not running on cached page

I want to run a short script every time we get a new visitor to the site, which saves a cookie with their landing page and their source.

 I’ve written this code and it works as expected and I have hooked it to the “send_headers” hook. I chose this hook because I believe it’s the earliest hook where global $post is set, which I need.

However… when we have caching on our Siteground site the script often doesn’t run on the first page load, presumably when the visitor is being served a cached page.

For example, often if a visit starts on the Homepage the script doesn’t run. It then runs later when they visit an uncached page.

This means our code doesn’t work as expected.

I have added our cookie “bnfo_settings” to the “sgo_bypass_cookies” filter but this hasn’t worked.

Can you provide any guidance of how I can make sure this script is always run please? Obviously I don’t want to turn caching off.

Thank you!

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