Roles removed from user with roles the role-editor cannot set

Setup:

User 2: administrator / moderator / editor
User 3: role_editor | Is able to assign role "editor" to people

Problem:

When user 3 edits user's 2 account, all roles that user 3 is not able to set, are removed from user 2. So user 2 end up with only the editor role if user 3 edits user's 2 account.