steertalker mentioned if you are coming to full draw when shooting from your treestand. With a bow longer than the average arrow; its difficult to get in a position in treestands where you come to a complete draw.
There is another gorilla in the room; that is your personal attitude. When you release an arrow; you can do more bad in a split second with a trad bow- than you perhaps can with a 'whatever those bow things are called now' bow. ( that IS a guess )
I can neuter a gnat with one shot; and miss by three feet the next - if I am not in total control until the arrow hits the target.
If your carrying the burden of thinking failure; it could be affecting your release; and therefore the shot. So too can being OVER confidant in your shooting... to where when you shoot at animals; you can loose concentration at the release.
Arrows can porpoise; they can wiggle back and forth- like a salmon about to jump the hoover dam.
First thing in your description that came to my mind was sharpness of the broadhead. Second was that your release might be bad.
With the hit description you should have killed the deer; but you did sound a bit defeatist in how you looked at the situation after the hit. That could effect your tracking of the deer.
I have put arrows totally through elk; deer; bears etc; and I have also killed many animals where the arrow did NOT pass through.
This fall I shot under a deer; hitting its front leg way down low; and with some hard tracking - I got that deer. Its not all about blood sign; its about figuring out where the animal is going; if it tends to go left or right at obstacles; the side its hit on; the cover; the distance between imprints. A hit deer will leave a more distinct track...
But I can tell you that if your not committed to finding the animal- due to weather or doubt of somekind; it is not going to help your tracking.
I shoot two blade broadheads; and 4 blade zwickeys; which have not so much 4 blades as two tiny blades that seem to relieve the friction on the arrow surface- more than anything. I do not - because of experience with all kinds of game - shoot real 4 blade heads. If your release is not perfect using a 3 or 4 blade CAN screw up a kill.
When I was tracking lots of bears hit with the new 'compound bow'; they were often not tuned. The arrows would come out porpoising; and when they hit ribs; they would stop right there.
Three blade heads would hit with two blades; the untuned arrow would sent energy to the remaining blade; and the arrow would often actually flip over or under the bear. We often would see a bear shot this way a week later when it fell to another arrow; and I had a degree at that time: in what we now call criminal forensics. I inspected each wound with great seriousness.
Then; as now - tuning a bow was a big factor in the ability of an arrow to penetrate. So is release.
Keep your broadheads sharp; tune that bow; watch your arrow flight up to 80 yards; and do not give up. You can kill a deer with your bow !
Traditional archery will not give up on you; please do not give up on traditional archery