I received a response back from ESRI Tech Support and they confirmed that:
"If you use another coordinate system other than the default basemaps' Web Mercator coordinate system, the Coordinate widget overrides the maps onClick event, and the popups no longer appear."
They say that:
"This seems to be by design as all tool widgets that use the onClick event override the feature popup when the tool is active. Without customizing the widget to use a different event handler (such as right-click) you will not be able to have both the feature popup and Coordinate widget work at the same time."
So basically this is how it was designed so I am doubting there will be a fix.
A suggested work around that they provided was:
"When editing the Coordinate widget in WAB, add your desired coordinate system to the list. When you want to see feature popups you will click on the widget at the bottom of the application and choose the Web Mercator coordinate system from the drop-down list. The maps onClick event will no longer be mapped to the Coordinate widget and the popups will work again. You can then navigate back to your UTM zone coordinate system to togglethe Coordinate widget back to the onClick event."
Hope this helps anyone that is having similar issues.
Regards,
Michael