We've all made the same mistake, or most of us anyway.

Something else I just thought to mention. It's hard to visualize the actual hit from a story but another thought is that the shot was simply too high and not necessarily too far forward. The fact that your penetration was limited almost certainly tells us that a bone was hit. If the arrow is at the best height, you have to hit very well forward to get that legbone. I've helped many a bowhunter friend track shoulder hit deer and had a few experiences myself and many shots thought to be too far forward are actually too high instead.

Was the buck relaxed or on alert? An alert deer can drop considerably at the sound of a bowstring.

Look at some deer anatomy photos, watch some slo-mo video of deer reacting (dropping and springing) to a bowshot and replay the shot in your mind and you may deduce that the deer was hit a bit high.

Maybe you already know this stuff but I hope you find something helpful in my rambling......