I hadn't thought of it being a learnt behavior might very well be. Since I got her I've been finding holes in her training and bad habits and slowly have been patching them up, maybe she hasn't even been taught about excepting any contact. Ugh just another thing to work on.
$40 isn't a lot to spend on a bit, I just can't afford to buy two or three that won't work, $80 to $120 is a lot right now.
She's having her teeth looked at soon, so I'll talk to the vet.