If you have moved a file from one R Drive to another, or sometimes even to a different folder within the same R Drive, some of your colleagues may lose access to that file.
Access to specific R Drives and their individual folders are not granted automatically, they need to be requested for each employee. This is because each individual position within a department may need access to different R Drives for any number of reasons (work with other departments, confidentiality, etc.). If you move a file from one R Drive to a completely different one, then anyone who doesn't have access to the new one won't be able to find it anymore (even if it is in their "recent" documents.
Similarly, while it is requested for most employees to get "top level" access to a folder, there are also cases where it is requested for someone from another department to access another R Drive, but they only need access to a specific subfolder, which is a valid request. If you have moved a file from that subfolder to a different one, the person with limited access would no longer be able to find it.