It it is doing caching then my first thought is that this caching is interfering with the refreshing of the pages, which is why setting it to developer mode may have cleared up the problem. My next question would be: Why are admin pages being cached since this is where you’d want to see changes being made?
You may want to open a new support ticket https://support.advancedcustomfields.com/new-ticket/
or contact help for cloudflare
