Prepopulated value is used even when field value is set to "none".

I have a Entity Reference field that is being prepopulated with [current-user:uid]. This works great except when the user wants to change the field's value to "none" instead of using the prepopulated value. It then always uses the prepopulated value instead. However, when the value is changed to a different value (other than none and the prepopulated value), it works as expected.

Any help would be greatly appreciated. Thanks in advance.