Runtime Feature Layers Not Detected by fetchPopupFeatures() in 5.1

[JeffreyThompson2]

I have been trying to build an application that can work even if the Enterprise Portal goes down. Because of this limitation, layers must be added at runtime. I cannot depend on a Webmap.

I have not been able to find a non-deprecated way to get a Popup, Feature, or Features Component to detect a Feature or Map Image Layer that has been loaded at runtime. I've tried the new fetchPopupFeatures() function, the standard Popup and even directly calling hitTest(). 

I have created a sample in CodePen. The sample has both a standard Popup enabled and a Features Component. The data that is pre-loaded in the Webmap is detected by both. I has added a layer of bigfoot sighting, symbolized by orange balls. This layer is not being found by either.

https://codepen.io/editor/jeffrey-thompson/pen/019fd25d-36cf-71a1-95fa-388574bc8f31

I was able get my application working by using the deprecated fetchFeatures() function. These lines are commented out in my CodePen, but do not appear to work in the sample either.