Same here, thanks for the pics.
I replaced the same thing 2 months ago and the plastic bushing that encases the bolt is a real SOB to pound out.
(I used Moog bolts, but same thing....)
I ended up melting the @#$%^!$%^ plastic off with a torch, then even more kicking and swearing.
Got it out though, took about 3 hours.
I have no idea why it would shear off the head of the bolt.
I suspect a -30 degree Wisconsin winter may have played a part. As stated earlier, I had NO idea it was busted.
Again, thanks for the pics, they should be included in the