I already experienced the same issue, after the addition of a new column in my sheet. Usually after several data refresh via the Glide editor the column name correctly appears. If I remember well, it also happened that the column name appeared few hours after, even with several refreshes in between.
Similar problem. When I created the app, I sorted the spreadsheet and inadvertently included the row of column titles in the sort. So my “field names” on the detail page were the values of the first row. I’ve corrected that, but the field names remain wrong. Everyone’s page shows a field name of scn566@gmail.com as the “email” field name. That’s the email of the first person in the spreadsheet.