The bent rod that the roller of the primer slide rides on determines how far the primer slide moves.
In your case, you probably got some powder grains inside the primer punch assembly. The primer punch did not fully retract, engaging the primer slide on the upstroke.
This forced the bar to bend inwards to the press ram, before the force dislodged the primer punch and the primer tray was released.
After you've restored the bar to where it originally was, clean the primer punch assembly out very well. It must be removed from the press to do it properly.
When powder spills on your shellplate, stop reloading, clean the shellplate and the primer punch assembly. If you get enough powder in there to jam it properly, you can break the primer slide, like I did.
Hornady sent me a replacement free of charge, even though I explained it was my own dumb fault.