This post goes over how to handle Cloudflare Pages subdomain cache.
To set up a subdomain for a Cloudflare Pages site, add a CNAME record.
Pages comes with built in caching defaults that are optimized for caching as much as possible, while providing the most up to date content. Every time you deploy an asset to Pages, the asset remains cached on the Cloudflare CDN until your next deployment. Therefore, you should avoid setting Page Rules or custom caching on your site.
To prevent double caching, set the Proxy status to DNS only so requests go straight to the origin server.
Another benefit of opting out of proxy is that the response times are faster since you save a redirect.