Currently, the Next.js Runtime v5 deletes all your Next.js-built HTML files from the deploy and uploads them to Netlify Blobs. Then, during the request time, the request is sent to the server handler where the HTML is downloaded from Blobs, processed by Next.js (checked for cache status) and a response is served.
I believe that’s what’s causing an issue in your case. On a surface level, this doesn’t appear to be related to the Next.js 14.2 upgrade, but we’ll keep checking.