Steps to reproduce the issue

Create a custom field type Media for Users.
Leave the parameter Directory set to - Use Default -
From frontend with a registered user add an image to the profile.
In backend now change the parameter Directory selecting a directory from the drop down list
In frontend with the same previous user try to select another image and look the media popup

Expected result

The user can now select or upload a photo in the directory set by the administrator

Actual result

The user see the default directory as the first time.
This behaviour seems to be just for users that already uploaded an image.
The users uploading the image for the first time, correctly see the directory set by the administrator