I see that often in winter and I think it's result of someone using the wipers either with blades frozen to the glass (not broken loose first) or by using the blades to move heavy snow off the glass.
The cure is easy. Turn the wipers on, turn the key off when the arm is up (12:00) and just push down at the base area of the arm (a few inches above the fastening point), re-bending the arm back into position. Works everytime.
You should then check the blade fasteners for tightness too.

Some will try to sell you a new wiper arm but there's no reason to do so.