Hi @jamesrsingleton, thanks for writing in detail about your testing. Let’s keep the SanityLive feature aside for the moment and first clear out the ISR part.
So, I recreated a simple example repo where I created 4 /blog routes with different generation and caching modes. I was able to get pretty good cache hits as you can see the image below. It will definitely be lesser for a real world scenario.
In my experience, pages rendered during build time are always cached and didn’t lead to function invocation. Whereas the pages built on demand are also generated only once and then served from the Edge Cache. ff in the path means only first fifty pages are rendered during build.
Only time I saw function invocation was when using revalidate (ISR) and cache expired. You can see the 304 STALE response and others where the cache is hit first and then function invocation happens.
I hope this helps.