Display labels created by script in ArcGIS Pro

[JeffreyThompson2]

I have a set of layers with complex labeling created in ArcGIS Pro that I am trying to display using the Javascript API through a custom widget in Experience Builder. The layers have been published to a MapServer in ArcGIS Enterprise and the labeling displays correctly in the Web MapViewer. However, the LabelingInfo on the REST endpoint is blank.

My custom widget converts the REST endpoint to a Feature Layer and adds it to my map.

I know I could write a script within my widget to add the labels back in, but that is not an ideal long-term solution. 

One possibility is to create a calculated field within ArcGIS Pro to use for labeling.  Has anyone else seen a similar problem and does anyone else have a better solution?