brushless motor glitching when operating steering

[jampat2004]

friend of mine just getting back into 10th buggy racing bought himself today from je,new lrp tc esc,new savox 1258,new hpi pro flux motor,he has got himself a second hand vantage type r 40 mhz radio set and when i say 2nd hand the set he has got has had no use and the condition is pristine never seen one as new looking.
the problem is when operating the steering left to right the esc is glitching making the motor turn slightly,there is no interference with the tranny so not sure whats going on,sure ive seen a post somewhere about new savox servos can be faulty sometimes causing problems.
has anyone out there had a similar problem can please post a solution.
thanks