Google Apps Script - Deploy as web app - now requires me to “Share” the the code

Question

I recently made a simple change to an google app script - once I re-deployed, you can access whichever page is in the:

var t = HtmlService.createTemplateFromFile('my1');

But any subsequent attempts to open a different html page by clicking a button with a link, will display "Google Drive - Access Denied" / "Google Drive, You need permission..."

I tested also, by creating a VERY simple web app, that does not attemp to access any google 'sheets', drive, or any other API, and get the same result - is the "Publish - Deploy as web app" broken?