changes in mxd and map service not shown in web map - arcgis online

Question

I am publishing a feature layer to ArcGIS Online directly from an mxd on my desktop, using shapefiles for layer sources.  The first webmap I create using this feature layer (which contains a few layers) works as expected, but when I add a new layer or remove a layer from the mxd and overwrite the service, the changes are not reflected in my web map.  Instead, the symbology and popups are misaligned; the layer names appear to be in the same order as they were before the mxd / service changes, while the symbols have updated to the new order in the updated mxd / service. 
Am I missing something here? I hope I don't need to rebuild the web map every time I make an edit to an mxd using this workflow? (I am using ArcGIS 10.4).
arcgis-online‌ feature-layer‌ web-map‌

MarkInsco · Answer

We also publish feature layers from .mxds and and overwrite the services.  It has been a few months since we've done that, but this week, many of our Web Apps had layers that fell out of index... even though the .mxds were not revisited/resaved/republished.  Is there anything else that could have caused this issue to occur?

JasonFitzsimmons · Answer

I describer my workflow in the original post.  I publish a feature layer directly from an mxd (logging into ArcGIS Online from File\Sign In), then add that feature layer to a web map. 
We need to use mxds (rather than setting symbology in ArcGIs Online) because our clients need to choose their own symbologies and layer order.  We then receive the mxd from them and publish.

KellyGerrow · Answer

How did you add the layer to the web map? As a rest service URL or as an Item from ArcGIS Online.

It sounds like symbology has been saved to the web map to layers that are referenced by layer numbers. When the data under a specific layer number changes, it seems that the web map is still the layer number and not the updated layer. There are a few ways to avoid this.

1. Always add hosted feature layers as items to Web Maps. This allows the web map to reference the item, which is updated when symbology changes on the item.

2. Make all visualization changes on the visualization tab for the hosted feature layer. If you add the layer as an item, the changes will flow into the web map that references the item. If you save symbology to the web map, the symbology will be saved in the web map where it won't be read updates that are made to the layer item.

Let me know if this helps.

-Kelly