different google IP address than Nginx access Log

My new built website. I added Clicky tracking code.

I found IPv4: 66.249.74.12 In Clicky visitor log
I cannot find 66.249.74.12 in my Nginx access log.

I only found 66.249.66.34 in my Nginx access log, and this IP does not show in Click.

Why google IP is different from the two logs?

Hi, I see that IP resolves to Googlebot. Did the time stamps match? If not you probably are seeing a different visit, but it's strange that your logs wouldn't see it.

Otherwise, Google may route traffic internally to request every network resource from Google's closest data center possible to each resource's host IP address, which could result in different IPs being seen by us vs your server, as the requests may be coming from different places. I don't know if that's what happened, but it can happen.