Bison No. 6 doesn't like me

Female bison No. 6 sailing towards me last week in a still image captured on my body cam.
Recently on more than one occasion bison No. 6 has let me know in no uncertain terms that she doesn't like me. Her main method of communicating this disdain has been to charge me at a full gallop.   
No. 6 charging me a few months ago. 
While this specific behavior from No. 6 is a recent development, I have noticed a greater amount of shyness in the past during emergency face fly permethrin treatments.  These treatments, which are normally joyous occasions for the rest of the herd, are so distasteful for No. 6 that she will not partake.  It seems as though she doesn't like the jostling and chaos that ensues during these treatments.

In my interactions with the bison I am very cautious and never approach the herd without at least one avenue for escape, which is probably why I'm alive today.  I have heard of instances in which people have bottle-raised individual bison and been able to develop close relationships with them, but my bison are wild and, even if they adored me to no end, I'd keep my distance.  As I see it, working in close proximity to bison without taking precautions is a lot like using a chainsaw naked.  You could probably get away with it if you were careful, but why risk it.