The "spike should reattach to the cap. Take the filter off the spike and see if it will not reattach with a twisting motion. AND WHILE IT IS APART LOOK FOR A ORING AT THE TOP OF THAT SPIKE, THERE IS A ORING COMES IN THE FILTER KIT, AND YOU CAN REPLACE WHILE IT IS APART! I'm not certain there is a oring up near the top of the spike, but inspect it and see if you spot one.
My spike came off one time while I was changing oil. I simple reattached it to the cap. That was a couple years age, several oil changes past, and it has remained in place ever since.