My iPhone 11 Pro Max has just overheated for the second time in a cool room while I was using it

If you mean a dialog appeared that said the phone was shutting down to cool off that is abnormal. Use the Contact Support link at the top of this page to arrange for a warranty repair/replacement.

If it just felt hot to you and continued operating there is no problem.

jeanfrombedford wrote:

My iPhone 11 Pro Max has just overheated for the second time in a cool room while I was using it This is unacceptable for such an expensive phone which I bought out right. I wish I kept my 8+ which is the one I am using to write this post now. I want to know Apple solution to this issue if there is one or is the phone just crap I’ve had other problems with it too

So your phone was in a "cool room" while it was sitting there by itself not being used, is that correct?

OR you where in a "cool room" and using the phone which caused it to over heat, if so maybe explain what you were doing with the phone to make it overheat.

More than likely due to poor cellular data signal.