Gotta bear in mind that these modern trains are ridiculously complicated (not like say, Big Dipper's, which are buzz bars), the more complex a device, the more that can go wrong with it... Either simple or complicated fixes...
Thorpe's issues go back longer than this year alone mind, but it's been widely publicised about their maintanance budget issues this year, I would assume it's either sheer dumb unlucky times, or just that lack of budget and engineers is causing all the issues...