We have Klaviyo dedicated click tracking set up through Cloudflare using the default settings using Page Rules with full SSL to the trk subdomain. Some hits are getting unsecure page alerts. Not sure why this is happening and struggling to recreate the issue.
That’s an insecure setting to begin with, I am afraid. I’d change that first to Full Strict.
Your screenshot unfortunately suggests that your server may not be properly configured, so I’d pause Cloudflare to make sure everything loads fine on HTTPS, contact the host if it doesn’t, and once everything was fixed, you can enable Cloudflare again.