First one is a very old bug. Not sure if anything can be done, but here goes....
You get told a new PM has arrived, you open your inbox, but see no new messages. The only way to see it is to refresh the loaded page. Not a massive issue if you know what you are doing and know the bug, but a bug all the same and probably fools lots of members!
Second bug is all down to the changes when the voucher link was added. The Meassage panel now only shows "messages" and no longer "99 out of 100". You can probably guess why thats a problem! Whilst I know good housekeeping is good advice, often you have no clue that your mail box is full until you check your personal email box where you find a message "Your PM box is full".
Can this be returned to show the allocation of used mail once more to avoid the problem and alert you to the fact you need to clear some mail?