X220t digitizer pen issue

this is the first lenovo laptop i have
the x220t arrived few day ago
when i first turn it on, the digitizer pen didnt work very well.
the pen kept "hold left button" when i put it near the screen.
i thought the nib is stuck, so it works fine after i changed the nib.
but there is another issue,
when i shake the pen, i can hear something loose inside.(ta..ta..ta)
is that normal?
do i need to contact lenovo in order to change the pen?

sorry for my bad grammar.