Mount Windows share is read-only for one user and writeable for another!

I have shared a folder in Windows 10 and mounted the share in Ubuntu 22.04 via fstab with the following setting:

//192.168.xxx.xx/b/MySharedFolder /media/Share cifs vers=3.0,defaults,rw,credentials=/root/.pass

Evidently, the file in /root/.pass contains the credentials for the Windows share. The strange thing is that for a user johndoe@hotmail.com in that file, I have write access to the mounted location from within Ubuntu. For another user, of which I will call SomeUser, the mounted location is read only! Both of these users are given full permissions in Windows, although johndoe@hotmail.com is a Windows administrator. I did change the account of SomeUser to administrator but that didn't change things.

Alternatively, this has write access:

sudo mount -t cifs -o username=johndoe@hotmail.com,password=somepassword //192.168.xxx.xx/b/MySharedFolder /media/Share

but this does not:

sudo mount -t cifs -o username=SomeUser,password=somepassword //192.168.xxx.xx/b/MySharedFolder /media/Share

I would be grateful for anyone who can point out the cause of my issues.

Thanks in advance.