According to the help documentation, feature views should update with the hosted feature layer schema but this isn't happening for me. I added a field to the hosted layer via ArcGIS Pro instead of overwriting the layer, does this matter? The added field shows up fine in AGO on the original hosted layer.
By default, new fields will be turned off in the view definition of secondary view layers. If you want to see the new field in an already created view, navigate to the set definition tab and check on the new field to be visible.
Are you able to see the new field in the view definition settings?
Manage hosted feature layers—ArcGIS Online Help | ArcGIS
Wasn't sure what to do, so I deleted the view and recreated it. I'll try this next time.