I posted last week on my first deer taken with a mech., the G5 tekan. I got a complete pass through, it left an awesome blood trail and a huge entrance wound. However one of the blades completely snapped off on contact with a rib. Hence, my exit hole was smaller, but still about the same size as a muzzy hole.

For some reason it bothers me a little that something didnt work like it should. Is this a reason to go back to fixed or should I see it as the head did its job and things like that happen?

Head did its job sounds like to me. Hard to say what happened to that head while inside that animal and caused it to break.