Are you using CF as a proxy or only for DNS? I ask because I just went to check my domains on the dashboard (some purchased a few years ago, one purchased just a couple days ago), and none of them have Web Analytics enabled.
I have all my domains set to DNS only, so no CF proxy. Wondering if that is why?
I just went and switched them to DNS only, they were on Proxy by default, that also should have been opt-in. Maybe I missed the option while switching the nameservers because I did it in a hurry but still.