We have some large (many features) statewide datasets that we publish and use within ArcGIS Online. We've noticed that for the states' layers with the most features (ex. California, New York) that the filtering function in the new Map Viewer does not work. It will just get stuck here, even after a long time of waiting:
If I switch to opening the data in "Map Viewer Classic", the filter function works just fine for those states' layers. Is the filter function in the new Map Viewer more sensitive to allowing filtering on large datasets?
If you can share the layer/map I can help take a look. You can invite russell_jsapi to a group and share the content there.