Doesn't work for me either in 4.15 using Internet Explorer 11.
I receive the message:
SCRIPT438: Object doesn't support property or method 'forEach'
The Popup does not load properly.
The problem always shows up, if I set Display = A description from one field
Here's an example using a sandbox: https://jsfiddle.net/z6jLr2op/2/embedded/result,html
The problem occurs when using:
Instead, the following code works:
According to the doc, both PopupTemplates should work.