1/3 of arrow isn't a lot. Hate to hear that for the hunter (and you and Maxx.) You are going to have fun this season. I know it. Just realize there will be plenty of these. Not every deer you go to track is a dead deer. I had to really start screening before I took a track. Every Tom, Dick, and Harry thinks your dog will work miracles. Not going to find a deer they missed, or hit antler, or didn't put a lethal shot on him.
I am far from an expert. Truthfully, I'm not sure I was very good at it. One thing I learned though is you will need to read what Maxx is telling you. It is easy to know if he is getting it right or not if you made the track for training. Coming in blind and not knowing what the deer did makes it way tougher. You'll start picking up on what he is saying a little more on each track. Good luck on the next one!