Found part of the problem, I looked at my broadheads and they are SONIC HEADS 85 grain. The tip is the blade, no carbide tip. That's can't be a good choice!
This is referred to as cut on contact and is not the problem. In fact a COC head should lend itself to better penetration all things considered equal. I have been using the COC style(Magnus Stingers & SteelForce prem.)for a number of years and they have always done the job when I did mine. In fact I found they out preformed the chisel tip fixed heads I use to shoot in many cases(Muzzy, TH, etc). I have no experience with the sonic head itself so just replying to the fact you felt a COC style may have been part of the problem vs a chisel tipped head.
I would look at the shooter. Firstcheck if thebow is tuned properly for the arrow/head combo? Are you using the correct spined arrows for the setup? Secondly, shot placement! Did you possibly crowd the front shoulder somewhat and get the scapula. Did you actually shoot high get the underside of the spine? It is very easy for the events to become clouded, it happens daily in the hunting woods.
Not saying you should switch heads but I also am not sure that is the reason for these events...do whatever you need to head back confident.
Good Luck