I have come across an issue with a few of my organizations hosted feature layers on our ArcGIS online account and mobile field applications. Randomly I will have a layer that will no longer allow me to make edits in the map viewer online and at the same time will give an error message on the field apps such as collector saying "Value is already present in the coded value domain." and will not load the layers. The layers have not been accessed or edited prior to this happening. I have tried changing settings, appending data, changing layer settings like symbology etc and nothing works. Even creating another layer from the template and appending the same data will not work. The only way I have been able to "fix" this has been to create a new layer all together from scratch and then upload with the same data and add it to the existing web map. I would like to find a way to fix the current "corrupted" layer as I lose all the attachments when having to start from scratch and am worried about my files that have thousands of attachments in place. Has anyone else come across this issue and know a way to fix my current feature layers?