var results = await MapManager.Instance.POIFeatureTable.PopulateFromServiceAsync(queryParams, false, outfields);

Esri.ArcGISRuntime.ArcGISRuntimeException: Cannot call this method in this context: Populate service can only be called when Feature request mode is manual cache.

var results = await MapManager.Instance.POILayer.SelectFeaturesAsync(queryParams, SelectionMode.New);