Renaming individual emails in outlook – Sync issue up to exchange

I believe I have come across a sync issue with outlook for mac 2011 but I'm looking for some confirmation...

I have a user who renames the subjects of his emails to help with searching for them again later on (simple enough). However it looks as if these changes do not update to the exchange server as when I log onto the mailbox via OWA or windows outlook, the subjects are all the originals. I've tested changing the subjects via windows outlook and OWA and the changes do replicate to all platforms. Seems to be yet again another outlook for mac flaw, has anyone come across this?

Thanks