Unread messages in inbox list no longer bold

[Julie]

We use Exchange Server with Outlook clients. Usually, any
unread messages in the inbox appear in the message list in bold.

One person's inbox has stopped doing this. The only change
is this person's new Blackberry which is set up to check
Exchange Server via POP3 for messages, leaving them on the
server.

Does a message retrieval from Exchange via POP3 remove
some attribute inside Exchange so that it will no longer appear
in bold within Outlook?

Thanks.