Tableau support have advised that the file appeared to be corrupted due to it not completely saving properly.
I was saving the file as I went, but unfortunately something must have happened when I saved it for the last time prior to finishing work on it and it meant that the file was corrupted then.
This does not appear to be a Tableau-specific issue.
I'm seeing this error as well. Other products have no problem saving to the shared drive. This is a Tableau specific issue.
An error has occured: Error: loomDocFmtResourceBundle-CorruptLoomFileExceptionMsg at e.json.then.t (https://127.0.0.1:60048/app.js:1:207171) at <anonymous>