on further inspection it does seem the main.[HASH].js file is not being updated. Hard reloading via clearing cache does load the correct hashed js file. Is there a way to tell App Platform to clear the cache on deploy to the client?

For anyone who finds this, I believe I fixed it with the use of react-clear-cache to conditionally check for latest production builds. I also enabled the service worker in create react app via serviceWorker.register() in the top level index.js

After even further investigation, the react-clear-cache did not do the trick. Still looking for a solution to this.