Some folders moved from Shared Drive to My Drive.

Issue:

The user(A) moved folders from a Shared Drive to his My Drive, but for a few folders, it is showing me (user B) as the owner.

Now, want to know how the ownership changed for user B.

Troubleshooting:

Taken a call with the user.

• The user showed the issue that as a super admin (user B) of the organization, User B gave the manager access to the shared drive to User A to move the shared drive to My Drive.
• User A moved the shared drive Marketing and North America to his My Drive.
• These two drives were two different drives when they were in the shared drive.
• There are some folders in the North America Shared drive (containing 1 TB of data) that are showing User B (me)as the owner of the files.
• I have collected the Doc ID and the screenshot of the drive logs where it says"due to a change in the parent folder, the folder permission for User A changed from none to the owner in Google Drive".

Resolution:

After further research on this, "due to a change in the parent folder, the folder permission for User B changed from none to the owner in Google Drive" It means that if someone had access to the shared drive to that specific folder, they should be losing any type of access, meaning that he will be unable to see the content of that folder unless the new owner shares it once again[1][2].

However, regarding the limit-related question that you asked, It happens that the real limit in a shared drive is not the storage that it takes, is the maximum of items, meaning files, documents, and folders, this item cap is a maximum of 400,000 items[3].

If you use the feature to “Transfer ownership” from the Admin console, the previous owner can still edit any transferred files, unless you delete their account or change their permissions[4]. The structure of the folders shouldn't be modified and should stay as normal the only thing that can affect is some files are owned by someone else, meaning if “user A” has files owned by “user C”, user B shouldn't see those files since they are owned by someone else.

Please note that Before transferring all your drive files to another user please make sure you do not have any legal holds applied to your account, if you have, it will through an error saying"Transfer failed ". Kindly remove the hold first from the drive and then transfer the data[5][6].


[1]https://support.google.com/a/answer/2789107
[2]https://support.google.com/a/answer/7374057
[3]https://support.google.com/a/users/answer/7338880
[4]https://support.google.com/a/answer/1247799
[5]https://support.google.com/vault/answer/9895152?hl=en&ref_topic=3215535
[6]https://support.google.com/vault/answer/11542069?hl=en&ref_topic=3215535

Google changed ownership of folders inside North America to you because when the user moved a shared drive(file or folder) into My Drive. As a result:

• Any permissions that the moved content inherited from the shared folder are removed. It inherits new permissions from the destination folder, in addition to other, explicitly set, permissions.
• In your case, the directory structure is too complex Storage is counted against the person who uploaded the file, not the owner of the folder. 
• When you manage large folder structures, child and parent folder permissions can be different. You can override inherited permissions of child folders to be different from the parent folder. You can also remove parent permissions from a child folder. This is why google system changed the ownership of some of the files to you. 

To summarize, If someone had access to the shared drive to any of the specific files/folders to My Drive, due to the large folder structure they change who can see it and what permissions apply to the item by the Google system.
https://support.google.com/a/answer/2789107?hl=en