I think jonath92 is @johnny on this forum....
Yes that's true. Actually the authentication used for onedrive for Business and onedrive for Personal is basically the same. I think @wandern is right with the URLs. It seems that there are two URLs which can be used to get the authentication Tokens from the onedrive api: https://login.microsoftonline.com and
https://login.live.com. The first one is used by joplin. This is has been already the case before I made the pull request for Onedrive for Business. But if you use this URL and you are logged in to a Business Account in office.com joplin automatically uses the Token from your Business Account when you click om the link even when you are logged in to your Personal Account at onedrive.com. However if you are not logged in to your Business Account at offife.com you can log in to your Personal or your Business Account. This is really confusing. So as far as I can see joplin basically has always used the "wrong" url for onedrive Personal. I am actually suprised that this hasn't been reported before. I think we need to have an option for onedrive Personal and onedrive for Business in the settings menu. I might make a pr for this when i find time. So propably not in the next 2 weeks