I did try republishing yesterday and I tried again just now from Pro to ArcGIS Online. Shared a web layer. Checked on enable editing, enable sync. Published to ArcGIS Online. In ArcGIS Online the hosted feature layer settings show that edits and sync are enabled. When I open the hosted feature layer in Map Viewer, the layer properties has Enable Editing toggled off. I can toggle Enable Editing on and add a point in ArcGIS Online from the web map, but if I save the web map, close, then open, Enable Editing is toggled off. Any insights?