I have been using Google Docs and Google Sheets for years together with the co-director of our company - switching between her account and my account when needed. Within the last couple of months I've suddenly noticed that documents that she has edited show up as having been edited by me! When I investigated, I discovered that when she opened a Google Doc from our shared account it would sometimes open it with her user (default for her) but sometimes as my user!
I also discovered today when changing the document locale on a Google Sheet it did the same thing. I had open the sheet with my user but when I changed the locale it changed it to my co-director's user account!
Has anyone else noticed this behaviour? Is there any obvious way to prevent it from happening other than logging out of the alternative account?