"you are not authorised to use this feature" in empty pm inbox for newly registered users

This happens with a fresh install, i.e. proSilver and the default permissions (newly registered users have NEVER permissions for "Can send private messages", "Can send messages to multiple users" and "Can send messages to groups"):

If a newly registered user opens his inbox and has not yet received a private message, then there is only the "Folder is 0% full (0 from 50 messages stored)" message and a bold one saying "We are sorry, but you are not authorised to use this feature. You may have just registered here and may need to participate more to be able to use this feature" (at the position where normal users read "no messages").

This message is probably displayed because of the "new pm" button which normal users see there, but it is very confusing as it makes users think they are not allowed to receive private messages as well, which is not the case.

Surprisingly this bug only appears when the inbox (or any other folder) is empty - as soon as there is at least one message in the folder, the misleading message disappears too.