Label feature weights assigned to a feature class in ArcGIS Pro 2.2 .mmpk (Mobile Map Package) file are not honored in ArcGIS Runtime SDK for. NET 100.3.
In ArcGIS Pro, the label class feature weight must be set to 1000 to prevent labels overlapping features. For more information see https://pro.arcgis.com/en/pro-app/help/mapping/text/prevent-labels-from-overlapping-certain-features.htm.