Sorry to see that, my friend (and thanks for the surprise in the mail a few months back....wow, just wow).
An issue we have as humans is that we when determine that an age class of deer are "prone" to or have a "tendency" to do this or that, we expect won't ever do the opposite. The definition of the terms tendency or prone means they actually will do the opposite, just not as much as what they tend or are prone to do.
My experiences line up with your beliefs, in that the bucks on the cusp of maturity (I see a buck as being fully mature when they reach 5 myself) have to fight more, in an effort to carve out a higher rung on the dominance ladder and when they must struggle to find an area to claim as their own. In my opinion, we must look at the big picture tendencies when trying to form beliefs on these topics. There will always be outliers. In fact, there will often be a good number of outliers, as there are pitifully few if any hard and fast rules to this stuff. We're merely trying to peg tendencies, after all.
We are the ones that seem to try so hard to assign rules to wild animals (I sure do, at least). Truth be told, when it comes to this type of stuff, the only "rule" I can think of that never gets broken is that every rule has its exceptions in the deer world.