Probably out of time.Don't know about Masseys,but most balers have a safety dog that stops the plunger from hitting the needles,if they are still in the chamber.
It is out of time and it is hitting a dog on the bottom that keeps your needles from getting sheared off. If I remember correctly you have to take off the brackets that hold the tie cams up top and roll the unit around by hand until it is back in time. My dad and I had problems with ours and it was a often occuring thing. I would need a picture of the tie mechanism to remember more.