I have editing enabled in both the drop More Options dropdown menu from the Content pane as well as settings in the Feature Layer (hosted)settings. I wasn’t having any issues with this until I exported a FGDB to My Content, and then the whole thing froze up. I also performed a synchronization with some offline data but didn’t actually make any edits.
The service was created a point feature layer (hosted) for Collector. It has been in use several weeks and has several hundred attachments and points. It is shared with a Group, and I have modified the domains using the JSON script earlier today but had no issues following this update.
Here is the REST API, but I don’t think you will have access to this since the information requires a company log-in.
I removed the token so that no one else can access your rest url, but it looks like the fields with the lock box are editable from the rest end point. Another place where you can disable editing is through the pop up configuration in the visualization tab or the map viewer. You can select Configure Pop up>Configure Attributes and then check on or off the capability to edit specific fields. If the edit option is checked off, you will also see the lock box in the data tab.
Try checking the pop up configuration to turn editing back on for the fields that you were displaying.
I'm thinking this should also be on the "Data" Tab in the "Item Details" of the service. Accessing the edit rights from the Map Viewer only is sorta out of the way, it's great to have it there if you are in a map, but sometimes you just need to edit data from the table view.
My pop-up had those fields as being un-editable, but I changed that, and I still had locks (but the locks were in Data>Table if I looked at it in the Feature Service details which is where I wanted to calculate fields). I was able to calculate the fields, after I made them editable, in the web map version of the table. I had exported the data previously, so maybe that's why they are locked in the Data>Table view?