This has been an issue recently: I can't always add annotations to files via a file view in the web client. I have administrator access to files contributors upload to a private staging folder in the AMP-AD Knowledge Portal project. I need to add annotations to these files. I have a private sandbox project that I am using to create file views of the data and annotate them (to keep the main project clean).
I can add a key to the file view schema, but it is not always updating the file annotations to have that key (I have had success for some keys, but not others). If I download the table, update the new key column with values and try to upload a new version of the view data, the values end up empty (even though they are shown in the preview).
I do not have an easy to see example because I cannot get this to work in a file view that doesn't have restricted access data; it works fine with all my silly project files. If I manage to get an example that doesn't require sharing settings to be changed, I will post it.