Stop in for a cup of coffee

Mattax said
Sumptin don't look right.

like this one looks to be bent in the threaded section
View attachment 1716112852

On the other one, it is true that the tension occurs on the threads nearest the tip. That's why full threaded machine screws are not usually needed and just make the bolt weaker.
Was the break inside the threaded hole?
Is there big spacer or bracket?

Threads do not go right up to the cap so that is good design even though its full threaded.
The failure area looks like it may have necked down a little, and the final tear is in reverse direction.
View attachment 1716112856

Broke off in the threaded hole. And yes, it’s bent in the threaded section, looks fractured just under that bottom flange

This is the hold down that goes on top of the injector and bolts to the head.

The shouldered goes in the head first, the hold down slides between the flanges.

The green circle is where the full threaded bolt goes.

The red circle, slides between the flanges of the shouldered bolt.

Both are too be torqued to 89 inch pounds in steps of 45 &44.