Map services published from ArcGIS Pro and added to a Map Viewer using the layer URL returns the error message, “The layer did not draw completely” even though the features did not exceed the maximum record count.
This issue is fixed in ArcGIS Server 10.8 as well as the ArcGIS Server 10.7.1 Map Services Drawing Patch available at https://support.esri.com/en/download/7756.