Free: Contests & Raffles.
Did you practice with your broadheads? I was using Muzzy's and had a heck of a time getting them tuned. Switched to a different BH and now I am much more consistent.
did you shoot another arrow to make sure it didnt do it again?
Did you drop your arm too soon?
1 grab another arrow check the arrow for any cracks,nics,cuts anything unusual and shoot it see and see how it does. It could of been a cracked arrow I had one that happened with at a 3-d shoot once, checked all arrows before it started then ten targets in whamo off in the woods it goes. 2 long shot here but did you feel any string slap or anything werid when you shot? I have heard of the bow string catching a piece of gear and the arrow keeps going but with out any force.
Force field around the deer.......strange stuff happens in the woods. Must not have been wearing your tinfoil hat?
With all the checking you did before you attempted the shot shoulds like the nock may have no been nock all the way, or the arrow was not on the rest properly. If you never had it happen before then its a good chance it was one of these two things.