I built a web application using the JS 4.4 API and have recently upgraded the JS source to 4.5. When I changed the script and style sources to 4.5, my Popup quit rendering the content.
Here is the content of the Graphic's popup template (which is logged during runtime to the console):
<div class='popupEntry'>Network: {Network}</div><div class='popupEntry'>County: {County}</div><div class='popupEntry'>Residential Buildings: {Residential_Bldgs}</div>
Here is the popup rendered in 4.4:

Here is the popup rendered in 4.5:

Also, my custom action is present in each, but only works in 4.4.
In 4.5 it throws an error "a is null" in MapView.js 1771:486
Browser: Firefox