When attempting to set a default raster function template for a hosted imagery layer in ArcGIS Online via the Settings > Imagery layer (hosted) section, the Save operation fails and the error message "There was an error updating the item" is returned.

Workaround

1. In ArcGIS Online, go to Content and open the item description for an imagery layer (hosted, *) where * is collection or multidimensional.
2. Open the imagery layer in Map Viewer.
3. On the Tools menu to the right, click Processing templates.
4. On the Processing templates menu, click + Import user defined template. All available templates displays.
5. Click the (+) icon underneath the template.
6. The selected template appears in the Processing templates menu.
7. Select the template to apply it. Click the Done button to close Processing templates.
8. Save the web map.

Steps to Reproduce