I have several excel & CSV documents loaded into AGOL WITH MY TIME ZONE SET that are consumed in dashboards. It is all fine and dandy for the first time I upload the document. However, when I overwrite the documents with the updated data, I lose my timezone and AGOL defaults it to UTC without the ability to change it. (Note: I am doing this manually, although I'd like to create some Jupyter Notebooks to read the data from my spreadsheets and publish to AGOL, but I have not had the time to accomplish this yet.)
I have tried overwriting both the file itself and the hosted table created from uploading it - and both methods result in my not being able to specify the timezone for the newly uploaded data. I would think that it would keep the time zone I set with the initial creation of the hosted table.
At this point, I feel like my only option would be to upload a new document, change the data source in all of my dashboard widgets, and delete the old source, which sounds preposterous and like a lot of unnecessary work.