This is just because the colours that the bot looks for on yaks are simmilar to those of the hairs / hides. You can safely edit the colours (play around with them) until the bot only clicks yaks. However jagex seems to be changing the colours in-game so you might have to re-do this process every now and then.
*btw OP. I love your script. It's got me about 3m xp so far, I've made a few tweaks since the day you posted it, and am working on making a GDK with your script as the skeleton! Trials has probably mentioned it somewhere.
for antibans, All you need to do with them in my opinion is make them occur far less and you'll be fine. As too much anti-ban isn't human
I'll post up a stolen procedure from narcle's fast-fighter to help with the infight.
As a small proggy type thing, The most I've ran it for so far, is about 16 hours with the modded {CRASHSMART} .Bat file, It works amazingly. Thankyou.