outlook calender sync - categories - bug or necessary

All my calender appointments are categorized after sync with the M8. Every entry has its own categorie for example 906402013310 and its not one of the main-catagories in my outlook. Does the M8 need this "code" to remember the dates or is it a bug?

is there another one with the same "problem"?

Not that this is a real problem, but i set my ActiveSync options to - only replace the items on the phone - and it still changes my outlook entries???

Thanks in advance!